Yes, the MacOS 3D drivers are in a pretty bad shape. I don't know if it is Apple's fault, or ATI's and Nvidia's. The drivers are a bit strange. Nvidia and ATI use a shared codebase for Windows and Linux drivers, but the MacOS drivers behave differently, so probably it is a separate line of drivers.
This mail in the mac-games-dev archive describes the situation quite well:
http://lists.apple.com/archives/Mac-games-dev/2007/Nov/msg00199.html
Also, one can get an impression by looking at the mac-opengl archives; Loads of bugs, and terrible workarounds. While "regular" game developers can deal with the buggy drivers by just not using various broken features our abilities are limited because we cannot modify the Windows games. If the games want to use something that is broken on MacOS we can't do anything.