Well, while my system isn't complete as of yet I can say that the sound quality is pretty good compared to having my head unit drive all 4 speakers. Also, I only have the front 2 speakers hooked up right now, using the 2 channel amp I plan to use for my sub. Even with only 80W (vs the 110W per channel amp i am waiting for) I can hear stuff I couldn't hear before, and there is no distortion unless you really blast the hell out of it.
As far as how good they are, i've talked to several people about soundstream amps and have heard nothing but good things about them.
And edge vs picasso, I was going to go with a 4 channel picasso which was a good deal more expensive than a 4 channel edge series. dnewma04 recommended goign with the edge series, cause anything more was overkill for my application. All depends on what you're looking for. Hit me up in a week when everything is working nicely and i'm sure i'll have more good to say.