iOS: Jasmine offers an absolutely gorgeous YouTube viewing experience on the iPhone and iPad that even the official apps can't compete with. And considering there is no official app for the iPad yet, it's a huge step up from the mobile site.
Google's freshly launched YouTube app for iPhone is great, but iPad users are still out in the cold until they get a dedicated app. Jasmine will have you log in to your YouTube account via OAUTH, and then it will grab your subscriptions, favourites, playlists and recently played videos. You can search by keyword, browse categories and popular videos — everything you would expect from a YouTube app. Jasmine even supports AirPlay.
What really makes Jasmine special are the little features and flourishes that make the app attractive and fun to use. The app has day and night themes you can toggle whenever you want, gives you access to YouTube comments (if you want) so you can post and read responses, and the app even filters spam. If you enjoy listening to music via YouTube, Jasmine also supports background play, so you can browse videos or leave the app while a music video plays in the background. Best of all, it's completely free.