I had an SDASS. The quality was fantastic, I thought it was going to stay on my love it list but....
I had problems with mine releasing an extra round from the magazine tube when I pushed it really hard for 3-gun. It got this really weird jam that could only be released with a knife or screwdriver and your not allowed to do that in most competitions! It was fine most of the time if going slow and yes, I was pumping it properly with that wonderful smooth spring assisted action. It was more reliable with the spring assist removed but I would most definitely not trust my life or competition to it. After much effort spent and a couple trips to gunsmiths later it was traded off to a dealer because I was to embarrassed to sell it to anyone. I did get a few fast stages with the spring assisted pump but it seemed to throw a wrench in the gears just often enough to p!ss me off.
I went back to a poorly made but more reliable new Remington 870.
Mine's awesome and loves the speed pumping, just like my GF does. Faster the better.