When downloading videos you've got several options available. From the main tab just tap any button to access the site in question – YouTube, Vimeo, Vine, LiveLeak, Instagram, and on and on and on. This program supports thousands of streaming sites. And an even simpler option is to just paste the link to a video straight into KeepVid.
The quality options when downloading videos are wide-ranging, though they always depend on each video individually. If a video is in 1080p, you can download it in 1080p, but also in 720p, 480p, or 320p. You can even download the videos as MP3s if all you want is the audio.
KeepVid is a very comprehensive video downloads app, with an interface that will remind you of similar apps.