I'm a long time veteran of playing the original UT. I first played it on a PowerMac 9600 with a 300 mhz 604e processor with no 3D acceleration back in the days of 8.6 and 9. Needless to say I've learned a lot about ini file tweaking for the UT games, especially for Macs. 😉
The UT experience is just horrible in OS X. So many numerous bugs that make it hard to swallow but I've sucked it up. It still isn't a pleasant experience.
Can't leave full screen, no 'preferences' command, glitchy, un-updated UT opengl driver, no TextureComposite support, no music, no control over brightness or sound volume, custom voice packs can be buggy in playback just to name a few. It truly is a crying shame the state it is in, in OS X.
I miss playing it on my 700 mhz G4 upgraded 9600 with a Voodoo 5 5500. I can't justify the desk space and extra cable mess to keep it hooked up just for one game (plus it is lacking a hard drive...). This is one of the real problems with the whole OS X switch is how these old OS 9 and older games got left in the dark. Either need an old Mac handy or the PC version and a PC.
One trick for OS X in UT with the ini file, is to add 'UseGammaCorrection=1' in the OpenGL section. This fixes those green boxes around biorifle goo and makes the lighting more accurate, but it also messes with transparent surfaces. So it's a trade off.