It's good to hear an unbiased pro and con about a gun. Funny how many people while owning a gun think it is fantastic but after selling it the gun then gets trashed reviews. I think that's called buyers remorse when the gun hype wore off. Gun hype has gotten me more than once.
The PPX sounds like a good gun for certain uses. IMO a gun is only great if it performs as you expect it to for the use it was bought for. I have never owned a Walther so I can't comment on them.