I've used thousands of Win and Tula/Wolf and they seem about the same to me. They're a little harder that Feds so I get an occasional FTF when shooting DA on my 625 which has a pretty light spring. However, this may be more my fault for not gorilla-arming them during the seating stage cause they always pop if I hit them again. If you are careful about seating they're fine.
ETA: you're asking about SPPs. I've had similar luck with them.
Last edited by gwalchmai; 07-30-2012 at 16:49..