I've used 'em...well, not the Wilson one, but the other buffer out there, that Tapco sells? Can't remember the name of it...
Anyway, it works fine! HOWEVER, there is a caveat: If you decide you want to use one, you should not use a NEW one, or one that's had more than a thousand rounds, in a carry gun.
New ones are too stiff, and will inhibit function for the first 100 or so rounds.
After about a thousand rounds, they start getting raggety. They become more a liability.
Think of 'em as a very high maintaince/replace often part, like o-rings on a space shuttle, and they _should_ be fine.
However, remember what happened with a faulty o-ring on the Challenger...
Personally, considering the loads I'm considering shooting and carrying for self-defence (DoubleTap...hot stuff), I'd need a buffer for range, and probably could use one, for carry.
IANAL, YMMV, proceed at your own risk, take this free advice for what you paid for it, etc