Having a similar dilemma, though $$ is certainly a factory so I expect pro would be the answer for me. However, when you start comparing all the extras, $1700-1900 makes sense in my mind. Really has a lot of stuff:
Adds 3D library mold
Adds 3D storage mold
Adds metal to subway ramp
HAS a subway ramp for storage facility (very cool)
Subs magna slings
Adds Ecto Goggles - I do think code updates will make this very cool
Adds playfield under rails (not a huge deal to me)
Adds right ramp
Miss anything?