I watched three episodes (the first two and the slumber party) and these are my impressions. Keep in mind, I do fall within the shows demographic target of 18-36 year old males, so I may be biased.

Pros:
Theme song is incredibly catchy, all of the musical numbers are well done.
Protagonist is named Twilight Sparkle (!)
Applejack is the cutest pony ever. Bar none. Except maybe the hyperactive pony whose name is escaping me at the moment.
Pillow fight?

Cons:
Only had time to watch 3 episodes
Spike is... meh. He's not so bad, but he annoys me some. Mainly because he can't compare to the magic of the other ponies.

Other thoughts:
So far it's struck me as a reinvention of Harry Potter, but with the power of love replaced by the power of friendship. Because it is magic.