1. ) They're heartwarming depression killers.
Being a guy I can't say I relate to the genre in any way, but I know a thing or two about depression. So a series that's filled with cutesy, energetic characters and endearing moments is the perfect remedy when you're feeling down. 

I don't mind if things get dark at times. Tragedies happen, but these girls have their friends for support, and their love for those around them can shine past any darkness that comes their way. That Power of Love song really expresses how I feel about the genre, especially the line "It gives meaning to each moment, it's what our hearts are all made of." That's the kind of feel good inspiring awesomeness I watch this genre for.

2. ) They are endearing tales of character development.
The Magical Girl genre for me is a testament to the growth and maturity of the protagonist, and how magic helps them achieve their goals. The key word of course is helps. It would leave a sour feeling for the viewer if these girls depended entirely on their powers, without some degree of inner strength and wisdom. Of course it's a long road between being clumsy and childish and becoming a strong, capable woman, a change that should never happen the moment the girl gets power.

3. ) Strong female protagonists.
One thing that typically bugs me about anime is the standard "Hero's girlfriend" character. She'll stand there 90% of the time with her hands clasped together, whimpering about how the protagonist needs to come back to her, or be safe on his journey. You're not gonna see that in this genre. The levels of butt-kicking vary but one thing remains constant. These girls are the heroes, and they'll do whatever it takes to protect the ones they love.

4. ) Kindness and innocence.
Fanservice characters and sociopaths have been two types of characters I've never been fond of, so I'm pleased to see a genre with characters who aren't just jerks for the sake of being jerks. If someone's a jerk (Lookin' at you, Fakir) there's usually a good reason for it, and they either grow out of it or die. The Magical Girls don't just immediately decide their enemy is pure scum and kill them off. They try to find out why they're acting the way they are and reason with them. And of course since the main demographic is young girls, you're not gonna see women cramming their massive jugs in people's faces or using their bodies to get what they want.

5. ) It's easier to understand when you have one of your own.
Not gonna lie. I wasn't fond of the genre until a couple years ago. I had the ignorance of people around me infecting my brain and telling me the genre's mainly a source of panty shots and nudity fanservice, for guys to drool over hot girls. One day I decided, as a joke that I could write one of my own, much better than any of that fanservice junk. So I watched an anime to gather up ideas. It was Pretty Sammy, and from the first episode I was inspired to turn one of my own characters into a Magical Girl. It went far better than I expected. Lots of hammering out over the years, but one thing stayed the same, I had a Green Eggs and Ham moment. I gained an appreciation for the genre once I gave it a proper try.

in no particular order

1- It's aesthetically pleasing to me. I love frills, mini-skirts, sparkles, pink, pastels, over saturated colors, cute hairstyles, transformations, school uniforms, bishonen, etc. Every stereotype magical girls has ever stood by (not counting ecchi ones) I absolutely love.

2 - I just grew up with them. Every time I find a new magical girl show or revisit an older one that hits my inner child just right it's like a hug from an old friend.

3 - It proves that you can be a toy commercial but still have heart. Alot of american animators who survived the 80s by drawing for complete sell-out cartoons have an absolute loathing for cartoons that have the #1 goal of "toy commercial" in mind (and understandably so tbh) but I watch something like Ojamajo Doremi - which is such a toy commercial sometimes it makes me laugh. But in the very same episode it'll make me feel so happy that I took the time to watch it.

4 - I can relate to it so much more than any other genre.

5 - They're just fun. How can  you not like them?

1. well cheese. I find some magical girl shows to be cheese and I personally love that. I mean come on Sailor Moon is full of cheese. Processed cheese food slices too.

2. I agree with Link up there, about the depression kicker. It works almost as well as video games for me. And Power of Love makes me cry every time I hear it. I love it!!

3.Each show uses the same elements in unique and different ways.

4. who doesn't love a talking animal side kick? My fave characters in magical girl anime usually end up being the side kick and the talking animal at that. I love Luna!

5. Through each of the magical girl animes i know i have gained friends.

1.) They tug at your heart, make you feel their struggle and live their emotions. 
2.) Rather than hate, they overcome the situation with love, trust and bonds.
3.) Gotta love that, despite their different attitudes, they TRUST each other with their life.
4.) Like Utena, I love snarker Sidekicks.
5.) They all have something to protect,rather than simply desstroy.

- CUTE THINGS!! I love cute things and MG shows are filled with them!!
-It's uplifting! These kinds of shows really do make you feel better. 
- Filled with Emotions! I have cried many times watching MG shows. Heck I cried in the Fresh Precure Movie over a toy almost losing its life. O.o
-Empowerment! These shows really encourage the viewer to become a better person. Great role models for little girls!

I seriously CAN NOT BELIEVE I have done this on the old MGConfessions forums!

Well that's going to change!

1. Growing up with the "heroism and girly themes"! Or in short: I love feminine things without anything that was mindless. I'm a (softcore) feminist and I love anything that was created for us, but with the same qualities of a super hero story.
2. The girls. Shy girls, cold girls, megane girls, ditzy girls... Growing with the bishounen fad, I don't feel "connected" except for humor or cute looks... But as I have became a bisexual woman, I admire the strong girls of all diversity. I also blame MLP. I love the female anatomy and appearances (and colored hair)... I can not stop. 
3. Depression killer. I give credit to Link for this. For being a girl who had semi-suicide moments (I am fine people!) before, that was before I got into the innocent lane as an adult with problems and got me to watch Smile PreCure after Madoka-Magica (the sad and polar opposite). Cure Happy was my anti-depressant drug. She's like my "idol" to move on and spat out "Ultra Happy" when it's needed.
4. The costumes! Looking around the harajuku fashion trends from sweet lolita to fairy kei, some of these cords and fashion choices were probably originate from the magical girl fad these ladies grew up with! I have seen a few photos where they are carrying Sailor Moon or PreCure toys! It makes me happy and encourages me to find my own style that incorporates my interests! 
5. Finally...  Well, I guess you can say that magical girls can take a story seirously when you think deeply into it. You can probably see a story about a girl who was similar to Batman's story, and still can get away. Even the fairies/animals/mascots can have it's own conflict as well! (I'm planning to make them as important story-wise and not just for show in my original MG idea...) It's simple and full of childhood hopes, but it can get better if the story was put into deep thought like Princess Tutu or Heartcatch PreCure (as far I herd from fans).

So yea. That's my list...

1. It's super fun
I mean, why wouldn't you love a magical girl series? It's just lighthearted buttkicking and awesomeness.

2. Interesting worlds
Normally the magical girl universes are very creative and interesting. 

3.  There's a character for everyone
You can pretty much find any character to relate to.

4. The costumes
The costumes guys. Need I say more? This just goes the show that girly does not equal weak and useless.

5. It was my anime introduction
Were it not for Sailor Moon, I probably would still hate anime. It really helped warmed me to the medium.

Number 1 is definitely tops, but the rest have no particular order.

1. Adorableness! Outfits, mascots, items and the girls themselves. 

2. Watching the interplay between showing off the toys and maintaining a strong story. Go! Princess Precure is doing a very good job of this so far, despite the sheer number of toys they have shown off.

3. Parodies! Majokko have been used to spoof almost everything (including themselves) and it is always hilarious.

4. Because they are for girls. Being the middle child (male) with an older and younger sister I grew up watching a lot of girl cartoons. That isn't to say I didn't watch a lot of boy cartoons, but it did leave me with a great appreciation for entertainment targeted to young females. Recently here in the USA there has been a dearth of quality animated programming for young girls so it's nice to see that good girl cartoons are still being made somewhere. 

5. Quality. Very few(if any) Mahou shoujo titles are just throwaway projects a studio would use to keep hold of a timeslot. Great care is spent on making the characters engaging, designs appealing, and stories entertaining. Even if I don't personally like a particular title I can appreciate quality for its own sake.

Here are my top 5 reasons for why I love Magical Girl shows:

1. Relatable characters.

2. Amazing storylines.

3. The Magical Girl genre was the first genre that got me into loving anime and manga in the first place.

4. Female characters being the heroes in their own stories.

5. The fashion and outfits.

First of all, say that the idea behind this thread is great. Reading what makes other people so fond of this wonderful genre is quite inspiring.

AHEM, so, my list, with no particular order of importance:

1. Cool, cute and yet powerful female protagonists. I love that concept so much I can't stop writing/drawing those myself.

2. The superhero parallels. Okay, anyone who knows this kinds of stories knows what I'm talking about: the secret identities, the world-conquering villains, good vs. evil, unique superpowers... you know the deal. Most of the "magical girl warrior" type of anime and manga share these elements with superhero comics/movies, and I happen to love those too!

3. The aesthetic. Wonderfully coreographed transformations, dream-like page layouts, gorgeously designed magical costumes, shiny giant sparkly attacks... you name it. This genre is full of awesome visuals

4. The blend between a "real" world and fantasy. Many times the magic of these girls is used in a world that is not aware of its existance, and that creates a very interesting contrast. 

5. The possitive values. The cuteness. The fluffiness. The innocence. The power of love, friendship, hope... That pure feeling of childish hope even in larger-than-life battles when the main girls seem to be losing, but deep down you know that they'll save the day in the end. I LOVE that, and sometimes, I need it. Many stories are dark, and sad, depressing... these are not. And they don't have to be. Aside from the ocassional deconstructions and parodies, the OG magical girl story should still be the lighthearted, heartwarming child-like fantasy it has always been well known for.

Phew... okay, I guess that's all. I've missed a few points, but overall, that's what made me fall in love with MG manga and anime. Hope I didn't bore you to death!