I had an '81 JCM800 2x12 and foolishly sold it to buy a nice van for my band to tour in. I turned a 200% profit but often miss that amp. This is the workhorse rock amp and the first really significant use of a master volume in a brit amp (apart from vampowers I guess). It doesn't sound like a plexi but its decidedly marshall. The 50 watt model is best for most musicians and that's what I had. My combo was loaded with amazing Marshall branded G1265 speakers with those large H dustcaps. Some have inferior 70 or 75 watt celestions. They sound okay though. Get 1 with vertical inputs if you can as the verticals are not board mounted and can be easily replaced if the plastic cliff jacks break (and they sometimes break). Other than that problem these amps are rock solid road warriors that rarely if ever crap out.
I give this combo 4 stars as she is entirely too heavy and the stock single handle is worthless. Yu will wanna add casters or at least additional handles (even if you have roadies and road cases). This is a lazy-man's set-and-forget marshall compared to what came before. A good crunch is not dependent on proper balance of EQ and Presence settings. It will do you right for any type of blues or rock and is the benchmark by which every mid-gain stage amplifier designed since the 70s should be judged.
I'm waiting for it to arrive any day now, so I don't want to rate, or say what I think about it just yet. Once I get a chance to play it, I will repost what I think about it.