I've been a long time fan of the Maxon stuff. I have owned a Japanese Domestic Market OD808 RI Overdrive since before Maxon was imported into the U.S. (It differs circuit-wise from the OD808s manufactured since.)
In the interest of full disclosure I was also very good friends with someone at Nisshin Onpa, Maxon's parent company, who is now deceased.
I have also tested pedals for Maxon such as the OOD-9, the OSD-9 and the VOP-9 when they were still being prototyped.
That out of the way, the CP-9Pro+ is my favorite compressor. It sounds like an expensive rack compressor and doesn't sound much like a pedal compressor.
I can let someone else speak for me in this case. A couple of years ago, the same sideman called me as he was driving home from Rock Block Music in Nashville. He was urged to try the CP-9Pro+ at the store and was absolutely raving about it to me, saying it was the most natural and nicest sounding compressor he'd ever heard.
He never did get it though. He gets a lot of gear given to him. Maybe I didn't take a hint and try to get him one for free?
Now that I think of it, that might be it...
It uses a dbx chip for compression, which makes it a little different than say, the CP-101, which as mentioned, is an optical compressor. That has a different sound, rather "transparent" to use that hoary cliché. There's a Country guitarist I know in Texas that didn't like it as he said that he couldn't tell if it was on. That's why I like the CP-101 — the compression is not an obvious squash. To each his own!
