I love mine. run schoeps cmc34s into it. the psp-3 was one of few highly portable preamps that provided the 12v phantom the cmc3 bodies need and so it was my default choice honestly. I love the sound - a great compliment to schoeps i think. It's very versatile, M/S options. invert switch, lasts forever (like 6 hours?) on 6AAs, the 1/8" out actually sounds good and is quite sturdy, and is quite nice for stealth applications when the need arises.
the one drawback imo to the psp-3 is the lack of qualified service technicians or spare parts. there is little to none of either anymore since the psp-3 was discontinued. if it breaks in a bad way, it could become a brick. I tried to get them to send me the specsheet, wiring diagram, or anything that could help a decent repair tech to follow, but got nothing.
new mine was like $700 i think.