even with my limited experience, i dont beleive backstabs are a good thing. i strip, wrap, and use a pair of niddle nose pliers to gently squeeze the wire around the terminal screw so its a loop, not a hook anymore, and tighten. takes alittle more time per outlet/switch, but i sleep better!
I still wouldn't use backstabs, and I'm not even sure I would use screw tightening backstabs. Screws will contact as much or more surface than the backstabs will and won't take much more time, and since they're wrapped, they'll hold better.
I'm with you on the spring loaded backstabs, but I think you may misunderstand what is meant by the screw tightening backstabs. The leviton Prograde receptacles have a screw tightening clamp terminal which is identical in design and function to the terminals on most panel breakers. It provides plenty of clamping force and contact area. I would venture to say *more* than a screw terminal. At any rate, my thought is that if it's good enough for connecting to a breaker in a panel, it's good enough for connecting to a receptacle.