I presently own the QA and will always consider it to be by "home-defence" tool. I traded the AS for an HK USP. Both P-99's were in .40S&W
The AS shoots great outta the box. It's your typical DA/SA pistol, and it shoots well. With its 4-point something barrel (which makes it non-prohibited), I shot 1.5-2" groups at 15 yards. Nothing to brag about, seeing as I could do 2-3" at 25 yards with a full-size .45, but not bad for a Tupperware 4 incher. It's a great pistol and needs no work (or at least, my Gen I didn't).
My Gen III Qa is a different story. If I'd paid the $1,200 CAN price tag these pistols are going for, I'd have been pissed big time. But I bought mine slightly used....
The QA is a sort of DA only with a precocked hammer. Trigger finger was in pain after 3-4 mags. The trigger pull is atrocious. It's supposed to be somewhere around 8 lbs. Mine went something like this;
4, 5, 6 8, 9 10, 12, 13 lbs BANG.
The trigger is supposed to smooth out after 500 rounds or so. Bullcrap, if you ask me. My used handgun already had around 500 rounds under her belt, I put on another coupla hundred. No difference. And groupings? What a joke! I could barely hit the target at 15 yards, let alone create a group worth mentioning. I was bummed, but I had initially bought this as a home-defence tool, so 25 yard accuracy wasn't really important.
Then I cleaned up the trigger action as per the instructions on the WaltherForums site. Group sizes went down from barely hitting the paper to groupings of around 2-3". I am very happy now.
The reason I wanted the QA is because of the take-down de-cocker. On the AS, you can de-#### the hammer by depressing the de-cocker located on the top of the slide. This simply puts the pistol back into DA (for the 1st shot) mode.
On the QA, however, a smaller decocker button in the same location is supposed to be used only to prepare for dis-assembly. So if one was to decock a chambered QA and unauthorized hands were to grab hold of it, it'd be as useful as a rock or book-end. However, pulling back a mere 3/8" of inch on the slide would put it back into the usual partially pre-cocked QA mode, and now you're huntin' bear

.
And that's why I still have my QA. And love it
PS: I've heard that the new (meaning 2008 and newer) QA's have much smoother triggers due to cleaning up of the transfer bar (which is one of the mods I did). So it is possible that a brand-new, 2008-manufactured pistol, will be satisfactory