yeah, none of those keyboards are alike at all.
The privia's are the most excellent digital pianos there are,
nothing can beat their action, not even keyboards 5 times it's price.
But it has no assingable faders/knobs, and doesn't even come with wheels.
There is also no MIDI THRU jacks. I have one, and use it specifically for piano.
I also have an Axiom. They are great for recording midi in general (unless you need good action) nearly EVERYTHING is assignable (faders, knobs, buttons, wheels, even transport buttons) and they come with 8 drum pads which is nice. The action is not even semi-weighted in my opinion, but I don't care about action unless I'm doing piano.
I wouldn't touch the keystations. The 88 Pro claims hammer action, but they have the same action as
the Prokeys 88, which has absolutely horrifying action. The other keystations, that have the semi-weighted action, barely have any features at all. If programing faders/knobs to midi commands is important to you, don't get it.
I think in your case, since you aren't interested in weighted action much, is to get an Axiom. They are great, I absolutely love them. I got a brand-new 61 off ebay for $260.