It's not just over Civ... but yes, I will admit, the Editor is kind of the straw that broke the camel's back for me.
I've been using an Apple computer in one form or another for 25 years now, and I really do think the Mac is the superior platform.
However, the software development world doesn't seem to think so. I'm getting really sick and tired of everything from graphics, database applications, peripherals, and everything else I can think of coming out either first on the PC, or exclusively for the PC. I'm tired of hurrying up and waiting. I'm tired of little or nor support from developers and vendors.
In short, I'm just tired.
Actually, it's not a matter of going over to the dark side because of Civ III for me, it's now becoming a matter of going over to PCs so I have the tools my PC using competitors have at the same time they have them. It really is a pain in the neck developing skills with application a year to two years later than your PC counterparts...especially when that experience affects whether or not I get hired, and how much my paycheck is.