I can't decide so I've got them both.
I actually prefer the long paddle release of the PPQ M1. It's natural for me to operate it with my middle finger without breaking my grip in the slightest. I use my thumb on the shorter HK paddle, and that takes a similar grip break like using a typical button mag release.
The PPQ seems a bit snappier, and it has a shorter trigger reset (not by much).
I'm on the fence about the 'ears' on the HK slide. They kind of annoy me visually when shooting, but they are functional...
I like how the PPQ Navy comes with a factory threaded barrel. I got the VP9 from Irunguns so I got a threaded barrel on my HK as well, so no complaints, but if I had to pay more to upgrade the barrel I'd be annoyed (I like threaded barrels) .
The PPQ Navy is rated to shoot underwater, but the HK will do this as well.
If I had to pick one.... I guess I'd take the PPQ, but it could really come down to a coin toss for me.