You're broadly correct in your assessment, Studebaker (some broadcast quality shows also get listed as soundboard quality).
Pro-shot DVD-Rs are generally ones which were filmed for TV broadcasts, often with multiple cameras.
The sound quality varies greatly; most of the very early (e.g. '72 & '73) Roxy shows are quite poor; for collectors and completists really. Conversely, even audience recordings in recent years can sound as reasonable as officially released live albums from the 70s.
Rockinconcerts.com offers a pretty good service and its packages seem to arrive from Canada quite quickly. Just a pity that more of the shows don't come with artwork.
Not that I'd want anyone to think that I condone bootlegging, you understand...
