According to the Walther rep at the Shot Show, it is still up in the air as to whether or not the original version of the PPQ with the paddle style magazine release will be discontinued.
I have both the first gen P99 and the original PPQ.
My P99 magazines will not work in my PPQ. The barrel feed ramp contacts the very top front of the magazine with the slide all the way to the rear.
I have not tried this, but it is my understanding that newer generation P99 magazines will work in the origional PPQ.
The original PPQ magazines will work in my old P99.
The PPQm2 has no magazine compatibility with the original PPQ or the P99. (Suck)
The magazine compatibility issue is kind of a bummer. After handling the m2 version of the PPQ it is my opinion that the original magazine release under the trigger guard is preferable. I noticed that the m2 button style magazine release is right where my thumb lives with the pistol in a firing grip. I speculate that I may accidentally eject the magazine during firing with the m2 system. I'm sure that experiences may vary in regards to this, and that with practice I could probably get used to it. I will say that my PPQ has the best trigger of any striker fired weapon that I have ever used, though it is quite close to my P99's single action trigger pull.
If I was in the market for a PPQ today, I would hold out for the m2 just to ensure a ready supply of magazines in the future. With the original PPQ's fate up in the air it would a safe bet that mags will get rare.
I have to throw this in - the new PPX was also on display at SHOT... It was moderately awful. I love my Walther pistols, but the PPX looked and felt awkward. They are marketing it as an entry level pistol at a lower price point.