|A few things here:
1) Whoever mentioned the marshall AVT does not realize that the AVT's are not true tube amplifiers. They have one pre amplifier tube. They sound beyond horrendous.
2) New marshalls are not very good, unless you mod them (the 2203 and 2204 jcm 800s are good though, just a different sound). They are still much better than, say, anything crate has ever made though.
3) Amongst the true tone gurus, it is common fact that Marshall has never produced a good,responsive clean. Ever. Mesa cleans are far superior, but are still not as good as a nice rebiased Fender Delux. (i know this from extensive recording in high class facilities.)
4)Marshall Mode 4 amps are, in fact, a large rip off. The power amp is solid state, which obviously clip at louder levels. Plainly, this sucks. The gain will not sound nearly as warm, as it is a solid state amp. Solid state poweramps are generally MUCH less than half as loud as tube counterparts. For example, a solid state amp that is 300 watts might be loud as 50 watts tube...and that's being generous.
5) The mode 4 is not anywhere near 3000 watts, you clearly don't have much electrical knowledge. It is 300 watts, no matter how many speakers you use, it is still 300 watts.
6) The mode 4 *does* in fact have a tube *pre* amp, but the real "tone" comes from the power amp, which I said is solid state on the mentioned model. It will not have tube warmth or responsiveness. Instead you get brittle farty-gain.
7) The blue voodoo is a *decent* beginner-intermediate amp. It is not professional quality whatsoever. Try taking one of those into a pro studio, they will laugh you out. It is far too noisy, lacks warmth, is very tinny, has a very unresponsive EQ, and has terrible reverb. Now you're thinking "BS I SAW SO-AND-SO USES THEM IN THE STUDIO." It's a lie, and if you think you saw them live, they either have different amps beneath the stage, or they gut their endorsed model and replace it with soldano, mesa, bogner, deizel, or matchless parts.
Mesas are great amplifiers, (jcm 800, 900, and anything before) Marshalls are great amplifiers. I would never choose one over the other, that would be silly. Different tones for different situations, don't hurt your own versatility. Or you could just buy a diezel and it will do everything. :)
Are they over priced? All gear is overpriced. Bare in mind that mesa is selling a handmade-in-the-USA product, which marshall, crate, peavey, yamaha, etc can not claim.