Seems pretty solid! I tested on iPhone 4, which I use for my subjective performance testing when comparing libraries.

Transitions worked nicely, both meme and YouTube video thumbnail views were smooth. Compared to a possible native implementation the image search didn't work that smoothly during image loading, but it was still usable after all images were loaded. Also the list view for long lists with presumably dynamic loading (UITableView style) wasn't that smooth during scrolling.

All in all, kudos for the good work!