I'm giving it a 9 - I use it with full distortion on ONLY. I'm playing duncan-loaded Charvel Model 6 thru JMP1 > Rocktron ProQ > Alesis Quadraverb4 > Marshall 9100 > (2) Marshall 4x12's (pretty decent rig, eh?). The JMP1 just kicks ass at the modern Marshall overcranked tone. Don't expect it to sound good without a BBE sonic maximizer or some type of outboard eq (ProQ is a killer piece - like a programmable BBE). Also, it MUST be used with a quality TUBE poweramp. (It amazes me to read some of these guys giving a piece a shitty review, then seeing they're plugging a junk guitar into it, and plugging the piece into some bullshit amp!) One more gripe, and then I'll stop - this ongoing debate about the JMP1 "being tube" vs. "being transistor"... HEY! Just plug the fucking thing in and play! Now - if you like what you hear, buy it, if not, don't buy it! I (and 99% of those who hear my rig) happen to really like the sound. I guess what I'm saying is, I've been able to get MONSTER tone out of the JMP1, and really don't care if it's the tubes OR the transistors doing it. In fact, if it really IS all transistor, then you get killer tone AND solid state reliability - I'm all for that. Also, I agree - the clean sounds pretty much suck... But..., do you buy a MARSHALL preamp/poweramp/cabs to get clean sounds?!?!?!
Wow, the cleans suck... hey, you know what else? Ferrari's get shitty gas mileage, and Pamela Anderson probably can't cook for shit! You just don't buy a Marshall amplifier for clean tones, never have, and hopefully never will. Think about it.
Bought new, never had any problems.
My bottom line - this is a GREAT value. I also own the M/B Triaxis, I'm not gonna go into a big comparison thing here - it's not fair to the Marshall. There are other pre's that do more sounds, do clean sounds well, do whatever, BUT, this thing (when paired-up and set-up well) is the ONLY pre I've heard that really does the miked Marshall thing convincingly. I wouldn't hesitate to buy again. For those thinking about getting one, just use a little intelligence in the rest of your setup, and you're gonna be rewarded with great tone.