Indeed. Free streaming of all songs, and the price is often cheaper than elsewhere since the profit margin for musicians is greater (Bandcamp takes 15% [1]). Also the fact that there are multiple formats to choose from (mp3,flac, ...) is a big plus. The only downside is the lack of any major label/big names (which for me I don't mind, but the general population does mind).

[1] http://bandcamp.com/pricing

Isn't the Bandcamp model just the iTunes model... except iTunes's been here for over 10 years?

Except iTunes don't stream all songs for free and don't give you a variety of formats to choose from? Then yeah, you could say that.

iTunes has 90 second samples, which is a big chunk of the song. Definitely enough for you to sample and decide if you want the whole thing.

Not for me it isn't. I much prefer to listen to the whole album all the way through a few times to see if it has any staying power. Previews are better than nothing but when you're competing with piracy you should strive to give the user the best experience possible.