I've had a Cambridge 640P for about a year, and I spent the first 10 months of that time singing its praises on this forum. It *is* uncommonly quiet and versatile, and I considered it to be very dynamic and extended. It certainly was a good outboard phono stage feeding a line stage as I had at that time.
Since then, however, I've found that my MM cartidge (AT150MLX) sounds better plugged directly into--are you ready for this--the phono stage built into my Onkyo A-9555 integrated amp. And it's not even close. The Onkyo is smoother and more organic sounding, and beats the Cambridge to hell when it comes to nuance, low level detail, lushness via detail in its proper perspective. Music is more involving; there's a better connection with the artist, and also gone is a persistent low-level midrange glare that I consistently got from the Cambridge.
I don't think it's the extra set of interconnects in the Cambridge signal chain. I'm using a 1M pair of AudioQuest interconnects made from PSC+ copper--that's single crystal six nines copper. It would add a dab of capacitance, though, but only after the phono stage.
Given my experience with the Onkyo (I got the entire integrated amp for $474) I think it's worthwhile to bump your search for a phono stage up by about $100. I would look into the $250 Creek OBH-18 (I've never been disappointed with Creek), $199 Musical Fidelity V-LPS, Clearaudio Nano ($350), or Rega Fono MM ($350). You might also be on the lookout for a used Musical Fidelity X-LPS, Lehmann Black Cube, or Grado PH-1.
PS: I've also heard the Peachtree integrated amps and I'm very impressed, both by the amp and its DAC.