I dont want to start any mac-pc stuff, but it seems to me that pcs are getting so cheap these days, and zbrush is such fantastic software.why would you want to wait for the mac version, or at least use a pc until the mac versions out? Theres some other fantastic softs like mudbrush I think only available on pc too.
I think gone are the days when anyone who's interested in CG only has one computer. They are such a commodity now that the flash one I bought 3 years ago is surpassed by even a lowend model today by the increased rendering power alone. I can also probably buy a second hand one on Trade Me thats just as good as my current machine for less than a few hundred dollars that will run zbrush fine. I cant remember what I paid for zbrush but it was lots more than that.
Just voicing a faintly puzzled question here so please dont shoot me