vTube for YouTube allows you to connect with your Google account to YouTube through a third-party interface that is cleaner and more responsive than most third-party apps. The result is an enjoyable, fast experience with a number of added features that only make the video viewing experience better.
Like most third-party apps, it's not required that you log in to your Google account directly to use vTube for YouTube, but to access most of the features you will eventually need to do so. As it is, most of the buttons you press will direct you to log in anyway. Once you do, there is deep integration here, allowing you to save, share, favorite, comment, and more with any video you find on YouTube. You can also interact with your playlists and channels from the app, as well. Categories are neatly laid out and the videos that pop up are genuinely fresh and interesting, not the same old "top 100" you see in most third-party apps. The interface is fast and responsive and works well with the new iOS 7 layout, and the search tools are very fast.
If you are looking for a good third-party app for YouTube access on your iPhone, consider downloading vTube for YouTube. It's free, fast, and offers numerous features that integrate with your Google account when you log in. It can be used as a browser or a full client depending on your needs and it's a great companion for frequent video sharing.