Of course, I'm a bit of a nutter and ordered the 5CD-6EP-1Book-Box-Set (directly from Bleep), but the individual Compilations (Chosen), (Unheard) and (Recreated) are all worth listening.
I still remember listening to John Peel's Music one evening back in 1990 on British Forces Radio, when he introduced a track simply with "And from Sheffield: Sweet Exorcist" & played a track from the "Test One " 12". It took quite a while before I gained control over my dropped jaw after hearing this track :)
There's really not much that compares to the feeling of hearing a song of a style/genre that you didn't have contact with before - and you find yourself thinking "Where was this music all my life?"
Another one from the same era is Lush's (sigh) De-Luxe.... now there is a band I would go to some length to see if they ever played live again (but without Chris, this will either not happen or won't be the same)...
