Jim -
I'm fairly certain there are supers at Oakmont, Merion, Huntington Valley, etc., who would tell you that firm and fast is indeed possible in August. I know the super at Oakmont will be expected to have it ready for the Open next year in June, I'd be surprised if he said August was that much different.
I've always felt if one had to go, I'd pick fast to go - I'd rather see firm than fast, if I had to choose. Nothing is as disappointing to me as playing on a nice summer day and having a ball sit down pretty much anywhere - I'm not the type of golfer that puts that much spin on it that I am capable of sucking it back on greens. Every once in a great while, maybe, but not as a rule. I think soft really makes things less fun.
I've always thought that most better golfers prefer the opposite - soft and fast. But, then again, I've always felt most golfers, especially "better" ones, want things to seem or appeardifficult - i.e. fast - but in fact want it to be relatively forgiving - i.e. soft.
Tom Paul's certainly one of the prime proponents of f&f, and I believe he has said he feels firm is the more important compenent, though ideally he wants both when possible.
Re: the PGA Tour, I've always thought it appeared soft and fast, but I've been told that it's a lot firmer than I think, those guys are just that good. I'm not good enough to tell.