We develop Infuse for iOS, so I'll chime in with a few of the big differences.
HW decoding
Infuse utilizes HW decoding, which allows for 1080p playback, even on older devices like the iPad 2. HW decoding also provides for MUCH better battery life, as the CPU does not need to be running at max capacity to keep up.
Automatic metadata
Infuse downloads movie/tv show info and artwork, and keeps everything organized.
trakt integration
If you're a trakt user (and if not you should be) Infuse will keep what you play in sync with your account.
Subtitles
In addition to supporting embedded and manually added subtitles, Infuse allows you to download subtitles on the fly from OpenSubtitles.org with just a few taps.
There are also a number of awesome things including multi-format AirPlay, Wi-Fi uploads, and more coming in Infuse 1.3, which is due in early August.