I'm with LML re the quality of unreleased material. It's a lot more hit-or-miss!
95% of the white labels I've listened to in shops have been shite.
Nearly all unsigned MP3s etc I've heard on the web are lacking in some way, and probably could not get signed.
Yes of course
some unreleased stuff is good. We're just saying, it hardly reflects on the DJ's abilities just because he's got a load of exclusive white labels or whatever.