I liked the episode, but it definitely wasn't my favourite.
It did feel kind of messy, and I didn't think it was as funny as Lesson Zero, although Pinkie was great =].
Although, I really, really liked the whole 'breaking in to get the spell' thing! =D.
It would be between Earth and Pegasus... Probably Pegasus, just for the ability to fly, but Earth ponies' special connection to nature is really good too, so it's a hard choice! =/.