which do you prefer? the JCM800 or JCM900? the 50 or 100 watt version? also what model of each since there's umpteen dozen of each one. I really want one of these heads, but don't know quite enough about them to make a decision and don't know anyone that has either one that I could play on. All I'm looking for is that great Marshall crunch, not versatility. this is the only true sound I lack in my amp arsenal. So, what are your opinions on these amps?