I've never heard the porta pros, but I have heard the KSC75's and the UR40's.
The KSC75's and UR40's sound very similar. I would say that the UR40's are a bit better because of the housing, but I haven't compared face to face.
As you can see in that thread, the KSC75 and UR40 share the same titanium coated driver, while the porta pro has the non-titanium driver.
I would do a few searches for porta pro vs KSC75, and KSC35 vs KSC75.
I think you'll find that the titanium coated drivers (UR40 and KSC75) have sparklier highs.
To answer the question, I think I'd prefer the UR40, cause I like the pretty treble. But, my opinion is highly biased because I;ve never heard a KSC35 based driver.