I'm using one. I like it quite a bit. I was using a Rockford symmetry epx before this. I believe much more dramatic improvements overall are possible with the 600. The only thing is if you really have it tweaked perfectly for you [driver's seat] the other listening positions sound like complete crap. It's not the processors fault, it's the nature of "signal delay". However, there are many presets so you can keep several combinations of settings handy. The seperate front/rear parametric eq. is a nice feature, as is the sub level control. I don't have
anything negative to say about it. The "self adjust mode" works alright, but I always made a few changes here and there after I used it. My feeling on processors in general is they can really make an already good sounding system really shine. You generally can't make a lousy system sound good with a processor, and I only adjust mine after I've done the best I can with speaker placement, passive crossover adjustments on components, level settings etc.
I don't think it's available new any more. Have you located one? If not, check the classifieds here, there's one for sale/trade.
If I haven't answered something thoroughly enough let me know, I'll detail it more.
