For the best performance running in OS9 is it. The current UTXp3 is playable but buggy and unfinished. Ryan is working on an offical UTX port for UTPG. Back to the "two weeks" deal.
For OSX play you need to do all the installs from OS 9 first. If you update to 436 in OSX it hoses the app. If you do the leg work and research you can get UTXp3 running. Once you get the installs done 436 will play the same as it does for the PC. ie no cd.
Now hosting from a Mac is a whole different story. It never has been stable. A Mac server needs to get rebooted everyday. I've used them in LANs and thats about it. They make fine servers, just have to babysit them.
Some good forums for info are at www.macaddict.com
Peace and welcome to the other side.
LOL I just noticed you've been to MA and posted about your server.