One of the things I prefer about the P99 trigger is how the drop safety works and the fact that the trigger shoe HAS NO CENTER BLADE. Unlike the PPQ and many others that use a 'center trigger blade', the P99 trigger shoe performs the same 'drop safety' function by pivoting on the trigger bar as opposed to the PPQ's center trigger shoe safety/blade needing to be completely depressed. On the back side of the trigger shoe, they're doing the same thing.....pivoting the 'nub' UP to clear the frame, enabling the trigger/trigger bar to continue rearward. On the PPQ, if you don't have your finger squarely across the trigger shoe when you start to pull, its possible to move the trigger bar rearward while NOT fully depressing the center trigger blade....then the trigger comes to a 'hard' stop. By contrast, trigger finger placement on the P99 is simply not a problem, as the entire trigger shoe is going to 'pivot', which means you can place your finger on the side/edge of the trigger shoe and pull and its gonna work.
When I'm at the range, that little center trigger blade starts to become a little uncomfortable. By contrast, the P99 trigger shoe is nice and smooth, and the curvature of the shoe fits my little girly/soft trigger-finger perfectly.
I agree with Jim....the market has spoken....most Americans seem to prefer 'buttons', hence the emergence of the PPQ M2. Some time after the M2 came out, I was talking to one of the Walther guys from Fort Smith....he said the PPQ M2 was outselling the PPQ M1 by 10 to 1. Yep, Uhmerikans love buttons.
As for DA/SA, Jim said it....the market has spoken.
As for PDP vs PPQ trigger, the market has spoken and Walther responded. The squeaky wheel got the grease....the PDP trigger, pre-travel/take-up is smoother and once you're at the wall, they reduced the creep......did they shorten the 'reset'.....I really can't tell on that one....I'm not even sure how to set up a measuring device to actually measure that.
P99 AS vs PDP.....they're both great pistols....pick the one you prefer, as its all about preferences. I have some of each. 😁