I bought two of the SP-10s, and two of the PSP-10s.
I've not experienced any problems with mine. I DID sell one of the SP-10s, and the new owner had a problem with a trigger group part breaking in the gripframe (can't remember which part.. I didn't keep the emails).
FWIU, he sent the gun in and got it back a week, or so, later.... repaired.
I've not had any further communication from him, so I assume all is well with him, now.
I really like both forms of the gun. Lightweight, no real recoil, just a fun plinker.
Some guys report failures with White Winchester, but that is all I've ever shot (except for a little S&B) in mine.
As soon as I get my shop moved, and back in operation, I plan to tool up a custom flashlight to place in that forearm hole. I think I'll make a laser housing, as well..... Maybe a combo head laser/lite thing.