I'm after Rush tones, along with some of the 80's metal, and a bit of the grunge stuff. This nails Rush - not just in high gain scenarios but also clean stuff (on clean1). I have a JCM2000, and a Fender HRD - what I was really looking for was a midi controlled JCM2000, and this is pretty close. It allows you to scoop the mids such that you could actually play accoustic and it'd give a hi-fi reproduction if required.. The fender, and to some extent, the Marshall JCM simply cannot do this. The Fender tone dials might as well read "Bass", "Midrange", "Other Midrange", and "More Midrange" -- which is all well and good for the classic overdrive channel, but simply sucks for playing clean (makes your fillings hurt). the JMP-1 let's you scoop the EQ, or push the mids, so you get the best of both worlds. Presense is a nice touch - increase presense as you increase volume, it adds some midrange back. There's a lot of compression, I suspect because of the opamps they've used - if you like a lot of tube punch, be sure to use a tube power amp, since this thing will not provide that punch.
I bought it used - built in 1994 - assuming same tubes - they still sound fine (i swapped 'em with some new ecc83's - no diff). There was a problem with the OD channels such that you'd here a constant crackle and fizz just above the noise floor, even with nothing plugged in. After a few hours of probing around, and freezing components, I came across an opamp that must of had some gunk build-up between the pins.. freezing/cleaning the opamp got rid of the noise. (rating a 6 since i had to fix this myself).
It's certainly worth the 375-400 they're selling for on ebay. I run it stereo thru a Fender HRD and Fender Stage (with a tcelectronic g-major in between).. tinker with the tone dials a bit, you can find your tone in there, it takes a bit of tweaking to uncover it. Heh it's not really stolen, i just thought I'd be funny to see "stolen" as a "purchase price" on harmony central.. I picked it up (legitamently) for 310US$ - really.