Snippits are perfect, there is no need for the entire track, period.
I'm not sure about you but when I purchase an album from an artist I've maybe only heard a couple times or don't know of, I want to HEAR a sample of what that album is about. I don't want to get it and then listen to it and be thinking what the fuck is this shit? I would never buy this. So snippits are essential in that sense, anybody not willing to use snippits probably isn't confident in their product and anybody willing to post entire songs, is just stupid, regardless if the album ends up getting bootlegged or not.
That's just how it works, that's the standard. If you look at any commercial online cd stores, they have 30 second snippits. Be happy with a minute or over a minute, that's more than enough.