the pro's are very nice, i've had a LOT of experience with them. i've also owned the Z's, and had a LOT of experience with those as well. but if you honestly can't hear the difference between the two, you need to take another listen to some setups that are set up right, not a display board. to get the Z's to sound right, they take a bit of tweaking. speakers on a demo board are just thrown up there 9 times out of 10 just to 'have' them on display. but once you get them right, the difference is night and day. the Z's are MUCH fuller, have a lot stronger midbass presence, smoother midrange, and much smoother tweets. the more advanced AMD in the Z's makes a big difference in tweeter response. at low volumes, the Z's still sound warmer but it's not a $400 difference. BUT... once you start cranking it, the Z's pull away from the pro's like no other. at high volume levels, the Z's keep crankin it out with great extension and linearity, while the pro's start to break down and lose some of that linearity and begin to 'hollow out' for lack of a better term.
take another listen to the Z's set up right... you will change your opinion rather quickly //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif i originally had a set of the SL60's, and they are a great sounding speaker. but i went from a set of SL60's to the Z6's and the Z's made the SL's sound like worn out paper crap OEM speakers. huge difference, and that was before i bi-amped the Z's.