I have an appointment to purchase one of these used, good condition, for under $500 - seems like a good deal for a 4x10 all-tube amp, especially Mesa Boogie, but there aren't many people out there carting around 4x10's, and I don't even see any videos on youtube of anyone demoing this amp, so I thought I'd throw this out there - good amp? Good buy? I figure since it's a few years old, I'll just bite the bullet and re-tube it right away with genuine Mesa tubes, so that's an extra $100 sunk, but otherwise I'm guessing it'll be a great amp for clean, rock (STP, VR, GNR, ACDC) or metal (Megadeth, Metallica, etc.)?