I test played one of these at my local store and instantly knew I'd found the right Marshall for me. I spent about a week considering the purchase and when it went on sale (Black Friday) I took it home. If you are considering this amp you're probably wondering:
 50 Watts - is that too much for home use? I'd say it comes down to where you live. This amp is easily capable volumes that support stage performance. Yes it has a "master volume", so you can turn it down. The only problem is that this amp's "magic" comes on at about 4 and seems to peek at about 7. 4 is LOUD, but not necessarily too loud for a single family dwelling. I'm able to push it to 7 w/o annoying my neighbors, but I've got a decent size yard. Do not buy if you live in an apartment as dialing it down below 4 kills the experience. Conversely if you're going to use it live it's loud enough for any club I can think of. Need more? Plug a 4 x 12 into it. Interestingly enough this amp will run the 4 x 12 while continuing to push the installed 2 x 12s at the same time. Pretty cool. Plenty loud.
 "vintage" - so does is have enough gain? All you'll need and likely more. Don't let the name give you the wrong idea, in the high dynamic mode this thing has super rich satruated thick high gain tones galore.
 "single channel" - is that enough? Short answer "YEP". As you've read by now if you've done your research, you're going to be going from your clean to your crunch off of the guitar's volume pot. It's got a footswitch to jump from the low dynamic mode (vintage OD) to the high dynamic (modern "modded" high gain), but generally you won't kick that during a performance since it drastically ups (or dumps) a significant amount of volume. Don't get wrapped up in that as a concern - trust me you'll select the dynamic mode that suits the song you're playing and you won't need the other one. If you are convinced you need "3 channels" worth of gain in a single song, you can get it by putting an overdrive pedal in front of the amp. You've got your clean on the low volume guitar pot - dial it up to crunch - and if you need a level of gain above that just kick your favorite OD pedal and it's all there. I paired it with a Vox Ice 9 OD and loved the results. I'm sure any good OD pedal would do the same.
 what's all the fuss about using the guitars volume knob? If you own a quality instrument, but you've never plugged into an amp that was it's equal then you've not really heard your guitar's voice yet. This amp totally displays you're unique instruments qualities - good or bad. Prior to trying this amp my volume knob was primarly an on/off dial for me. Furthermore my moddeling amp had homogonized my tone to where all my guitars sounded nearly identical. I had no idea the range of tones my guitars could command when paired to a quality tube amp.
This amp's strength seems to be what may at a glance appear to be it's limitations - it's dedication to a single channel set up. It uses two adjustments called "body" and "detail" to shape the pre-amp gain. Once you start fiddling with it you'll get the concept quick but trust me, you'll continue to discover tone possibilities for a long time to come. Exactly as advertised, - you truely can go from a beautiful clean to a great overdrive using just your guitars volume pot. Simple. At first I thought I wouldn't like dealing with that knob, but trust me dropping the guitar volume to clean up the sound does not make you loose volume in your performance and if you've got some good pick ups you'll discover why they're special.
 build quality is solid and the amp it very attractive in person. It's also larger than most photos make it look and pretty hefty to lift.
If you can't play one, listen to the demos posted on the Marshall website and then listen to some reviews on line. Just be careful since some "reviews" are not mic'd or recorded very well and completely fail to convey the amps tone or character.
Hope this helps you make a decision - trust me you'll love this thing.
Sadly the amp I took home had been a floor demo model and was about 3 years old. It had been rode pretty hard and had developed a slight filament rattle that was noticable at clean settings, so I've had to return it and am ordering a new one to replace it. This is not indicitive of the amps quality, but the nature of the beast when taking a chance on a floor model for a great price.