I'd played the JCM1 before and loved it. I watched some videos of both and thought the JVM sounded pretty much like the JCM plus extras (for a little less money, even) - it seemed to be almost the same sound, but with more gain available plus the clean channel, which has a nice sounding crunch when the preamp is cranked, a footswitch and effects loop (which I'll probably never use!).
Of course, this comes mostly from Marshall's own videos, so they can do all sorts to the sound, but I can try it at home for a few days and exchange it if I don't like it, so I figured I'd go for it. Should arrive tomorrow!
I still plan to build an isobox eventually, but that's not practical right now - when I'm more settled in my own place, I'll come back to that. In the mean time, a low watter like this should tide me over. I love the tone of these and they still sound great at 0.1W. I know they're not great value in some respects (I can find the JVM410H for less than double the price, although 2nd-hand) - I even looked at amp kits, but the best one I can find is 5W with a VVR, but I'm not sure it won't suck the tone (or even how good the tone is to start with).
Nice. The JVM's base sound is rooted in the JCM 800 2203. The big 100w version does a pretty damn convincing job at being a JCM 800 with a million more options. It's cool the little ones have that sound too. I really liked the JCM-1 myself. There's a guy here, minerman, he has the DSL-1 and gets some pretty damn amazing sounds from it. Congrats. Marshalls are awesome.