I should add that it will take a decent amount of time/tweaking to get whatever tones you're looking for. Like most programmable pieces of gear out there, the stock presets suck.
And I agree that a rack mount version would've been great. I love the convenience of having an entire rig all hooked up in a rack. Set up is so much quicker and easier. I don't think the the JMD series has sold well for Marshall, though, and I wouldn't be surprised if it has already been discontinued. :(
The first guy in the world to gig with an SM-1!!!
Kramer arch top Stagemaster Custom I, florescent pink
Kramer arch top Stagemaster Standard I, flip flop blue
Kramer Voyager (Kline Fantasy Wizard)
Kramer SM-1, Seymour Duncan version
Kramer Pacer Custom II, champagne
Custom Baretta, artwork by Beyond Custom Guitars
7 BC Rich's (2 Gunslinger Retros, USA Mockingbird, 3 Biches, Beast)
2 Gibsons (LP Classic, Explorer)
4 Jacksons (Bullseye & Blue Bengal DK2Ms, Kelly, King V)
70's Ibanez LP