My Little Pony: Friendship is Magic is easily one of the best children's shows I've ever seen. It never fails to make me smile, and that's sorely needed in this day and age where "dark" seems to be the name of the game for everything. I'm also amazed at how much I'm able to like every single character, from "the Mario" Twilight to the cute and random Pinkie Pie. I thought the show got much stronger in the second season, where it's become very creative. Delightful. My girlfriend and I cuddle up and watch an episode or two almost every evening.
That said, I don't understand the brony fanbase. It doesn't seem like the kind of show that merits a huge following--I would expect that from something like Star Trek or Star Wars. But is it a bad thing? No. I'm happy it's seen so much success.
I'm not a brony and never will be, but it really is a great show. To anyone deterred from watching it just because of the fanbase: don't be. You won't regret giving it a shot.