Good, but it has room for improvement.
This is certainly a good way to waste 20-30 minutes. The only problem I have with it, however, is that it's too easy. Unlike the guy who posted a while down, I didn't really have to cash whore at all until I hit level 9, but it only took me like 5 minutes to get everything (and I somehow ended up with $650,000 with nothing to buy at the end of the game).
The storyline was pretty cool... albeit very similar to GTA:SA. The whole 'being betrayed by your gang and friend' was a bit cliche, but you made it seem cool anyway.
The gameplay was also pretty fun. Normally, with these types of games, I get bored quick and quit out of them. This one was different. It kept me interested pretty much the entire time I played.
The graphics and controls were good too.
I guess I covered all the bases. So... yeah... this is a good game, and worth a play if you want to be unbored for 30 minutes. :P