This baby sounds awesome for something that began production in 1991. You can really create some beefy distortion patches or big warm jazz tones. You need to experiment with all the EQ and stuff first, but once you get used to it, you'll realise it's all there. The only problem that I have with it (as with all other solid state preamps) is that you have no real touch sensitivity which you can only get with 100% valve amps. If you want a very slightly overdriven tone you need to create a new patch rather than just working the volume knob on the guitar. The effects are pretty good too, but if thats all you want it for you should look somewhere else. Where it really shines is the preamp section. The effects are just a bonus. However having said that, the effects sound pretty good if you tweak them, theres a lot of versitility and there is a split feature where you can run some effects left and others right. It won't make me sell my Laney or Fender valve amps, but If you put this thing with a VALVE rackmount power amp and a really good sounding cabinet, you got yourself a really good sounding, very versitile, and portable setup. I'm quite impressed with the possibilities here but like I said, just wish it was more touch sensitive.
I dont know about the newer peavey stuff but the older gear from peavey was unbreakable. One thing I'd like to mention is that the Pro-fex II has a limited amout of memory. For example if you have a chain consisting of Compressor - distortion - 2 EQ's - chorus, there is no room to add anything else such as delay. Then if you are lucky enough to be able to add delay then try to adjust the delays parameters, it thinks "What's going on!? You're confusing me!!!" Then craps out. This isn't a reliability problem though but still worth mentioning. It still works as well as the day it would have come out of the factory.
My style of music ranges from Jazz to country to pop to Prog Rock. Been playing for about 9 years and also own Laney and Fender amps (valve of course). I believe I got a great purchase here for $500AUD including the profex II midi floor controller. You can usually find them cheap second hand. If I had the choice of buying a brand new preamp for $2000 then have to fork out another $800 just for a floor controller, or a quality used Pro-Fex II with the floor board for $500, I'd go with the Profex II again. I will never replace my valve amps, but for something so versitile and portable, you can't beat it. Please feel free to email me with questions or comments.