Threshold FET9 or Monolithic PS-1

Have an opportunity to acquire a Threshold FET9 preamp in mint condition. Curious what anybodys impressions are of the Monolithic PS-1/HC-1 phono stage and whether it will outperform the older FET9. Price is about the same.
I own a Monolithic PS-1. I have not auditioned the other piece. What I can say is that if I was to upgrade it would have to be a Klyne. The Monolithic is quiet, musical, dynamic, with deep bass (as deep as my DAC's). Stereo imaging and separation is fantastic. I consider it a true bargain. Everybody I know who owns one will tell you the same...