I've tried it, but it's one of those card games that's a little too arcane to be easily enjoyed. The goals are a bit nonstandard (which isn't bad) but that means it's much more difficult to understand the game. There are a lot of terms that seem vague, and the whole thing about being based around solving problems instead of easily understood combat definitely muddles the already confusing mechanics.
Don't get me wrong, I love card games. I have a Magic TG deck sitting on my shelf and an old binder of Yugioh cruff collecting dust in my closet, but I like my card games to be a little more straightforward, and the MLP game just isn't that. The resources are much too confounding for my tastes and I don't exactly think the source material is proper for a full on CCG treatment, at least not how it's presented.
Give it a go if you can, but be warned that it's not very intuitive at times, and downright befuddling at worst.