They're supposed to be different animals. The Pro VLA (and the MPA) got rave reviews, even going up against much more expensive units. And a lot of people hot rod them with killer tubes or a couple of mods that are floating around. ART also has a new comp out, the TCS II I believe, that is getting some good press (not just the hype the magazines get paid to feed us). That one's only a couple hundred quid, and it has several bells and whistles that make it stand way out of the pack in that price range!