I haven't owned many amps because I spent a lot of time saving up for my VH4, but I've played quite a few and this is my take (so far
Marshalls- I know Marshalls aren't made to be clean amps, but I need a decent clean channel for my style of playing, and I've never heard a Marshall with a clean that I've liked. This and the fact that I don't get to crank my amps loud very often. Marshalls obviously sound their best when the master is pushed, so it's irritating having to worry about buying extra equipment like a hotplate or something to get the sound I'm after. They sound awesome when you find one that you like and have a great guitar to match though! Thinking about buying another despite these complaints, go figure. Haven't played a JVM, people seem to be liking those...
Mesa- You have to spend a hell of a lot of time tweaking to find your sweet spot. Until you find it, things can be buzzy or muddy, depending on which model you have. When you find the sweet spot it kicks ass, but you have to go through a lot more effort to get to it than with other amps, IMHO. Great lead sounds, so-so rhythm. I hope to play a IIC+ someday, maybe even own one if the price is right.
Bogner- Never played one, but judging from the CDs I've listened to that have them and various clips on the net these are the most saturated of the bunch...which is why I really want one!
Diezel- This is where my bias lies, being a VH4 guy. F*cking awesome. Blows most Mesa/Marshalls away in terms of tonal variety and switching options. So glad that I saved up for one, though I haven't had the chance to play all of the different Diezels to see which model suits me best. I just got the VH4 based on reputation, and from the Diezel forum the Herbie is sounding more like my sort of thing (this has absolutely nothing to do with sound quality though, just personal taste in voicing). I'm in no way unhappy with my decision to go Diezel. This thing is both beautiful AND a beast. Tight as hell, amazing definition, and sounds great at all volume levels. You can easily hear the differences between guitars (through some amps, everything sounds the same). Oh, did I mention the awesome customer service on this board?
