OSX is great! The dock makes it so I don't have to wade through bunches of windows, multitasking means I can run mail, 3 IE windows, system prefs, terminal, and preview at the same time, with almost no slowdown. (It does slow down some if I start up Starcraft in the background, but that's to be expected.) I've even set Bryce 5 to rendering something, switched apps, and kept on working. It almost never crashes, it networks better, force quit works better, and it's a lot more hackable. It also looks better, which is both good and bad because the good looks slow it down. It does need lots of RAM, the best way to figure out how much is to put some in, run for a while, then open terminal and type vm_stat. If there's a number other than 0 next to "page outs" then you need more RAM. I have 384MBs and it runs fairly well on a beige 233mhz G3. Anything equal to or faster than my friend's G4 450mhz should run it great. Also, if you have a dual processor machine, OSX will speed it up a LOT.
Not being able to get on the net in X is wierd, normally it's much better at networking. Do you have an odd setup or something?