Hi
I can't speak about the UA apollo as I never used it.
I did used the UA plugins in early days and missed them a lot when I switch to Mac and Protools from Nuendo
I have been using the Aurora 16 Hd with protools for 10 solid years
I like the fact that it's giving me 32 I/O acting as 2 digi 192
Great for my analog and digital external gear patching.
My only caveat on the unit is the heat .
I keep it with a free rack space up and down in my rack.
The new Aurora 16n are running way cooler (first thing I checked at AES)
but you need deeper pocket
Francois