This thread is as good as any for my thoughts about the SPP.
I purchased mine for just under $700 way back in the day. I sold it a couple of years ago, almost doubling my $$$.
It was quite a shooter. The sights were marginal as they were very low to the housing, but were surprisingly effective. It was extremely accurate.
What really stunned me was that the power was nearly double as compared to what my SIg P226 would do with the same ammo. This was probably due to the big compensator on the front (in which the barrel would slide in). I had both a 15 rnd mag and a 30 rnd.
Taking it apart and putting back together was not an easy task, it took some "fineggilling." If you ever worked on IEC contactors, you know what I'm talking about.
The way the action worked was hard to believe. It was like quasi recoil gas operated rotating barrel something or other and was truly ingenious. It was the most dependable arm I had ever shot. It never ever did anything but spit cases out hard and put new ones back in place.
Recoil was almost non-existent. Pointability was top notch. The trigger really sucked. The trigger became worse as time went on. The sear was on a vertical post, and broke sideways. The pull wasn't hard, but had a strange feel to it. It had a very plastic feel, like taking the lid off of a tupperware container, or opening a ziplock bag. The slide lock was hard to operate.
After a while, I just couldn't find a practical use and I parted with it. It was neat to have for a while, and I do miss it from time to time. I don't feel any less armed not having it in my arsenal.