2 channels, 2 modes per channel.
Shared EQ. Effects loop, reverb with seperate controls per channel. Master volume on each channel.
Sound. Out of the four modes, I find three to be very useful.
Classic channel Clean mode delivers a very usable clean tone. It wil break up toward the last third of the gain curve, but before that you've got a range of cleans with a distinct Marshall flavour. Not as harmonically complex as a good Fender or dedicated clean amp, but they will see you through most playing situations.
Classic channel Crunch mode gets the typical old school Marshall crunch but doesn't sound quite as organic as a genuine old Marshall. Boosted with an overdrive it does a very good hardrock rhythm tone.
Ultra channel Lead 1 delivers hotrodded JCM 800 tones right out of the box. More than enough gain on tap for hard rock and old school metal. The best sound this amp has to offer. Back off the gain a bit and boost with your OD of choice and you're in high gain shred heaven.
The amp has a very simple control layout. Thanks to the good voicing of the channels you don't really miss a second set of tone controls.
Ultra channel Lead 2 is, for me personally, useless. Buzzy, dynamically dead gain that lacks all definition.
Same can be said for both the Deep and Tone Shift switches, the first boosting subsonics, the second cutting mids thus instantly wrecking the classic Marshall sound.
Crunch mode has a lot of bass compared to the other modes. Slightly imbalanced.
Lead 1 has a tendency to sound thin. A Tubescreamer solves the issue but there really shouldn't be an issue to begin with.
The effects loop is not very good, barely offering sufficient output to drive a delay pedal.
The amp blew up first gig I did with it due to a powersurge in te club's powergrid. It was fixed under warranty and the amp has worked flawlessly since. Has been my main gigging amp since 2006.
Marshall doesn't reply to emails. Other than that I have no experience with their customer support. The importer is worthless.
A great amp for people who want a variety of Marshall tones.
The price is right and, for my money, this is the best amp in the current Marshall line up.