Degeneration is probably going to please most big RE fans; it's officially canon, it has T-Virus zombies, Leon and Claire kick lots of arse, it has the G-Virus, and it makes reference to at least 2 of the games.
That said, you shouldn't expect this to be a work of art, because it isn't. It takes itself slightly too seriously at times, for one thing, which isn't aided by the slightly inconsistent voice acting (although to be fair it's better than what Resident Evil players are normally used to). The CG can be great at some points, but dips a little too far into the Uncanny Valley when focusing on human characters, especially when they're meant to be showing an extreme emotion. The story isn't going to win any awards, either.
That said, it IS a lot of fun to watch. Even the slightly crap parts are fun, because it feels more like you're watching a high budget B-Movie, and you end up just laughing at how silly or cheesy it is. It's probably worth the asking price for the bit where Leon throws his gun to Claire, whereupon the SFX guys decided to open a big ol' can of Bullet Time and apply it VERY liberally. Great fun, and for under a tenner you can't complain at that.