Somewhere in the Docs for OS X Public Beta, it mentions that Airport support is not enabled, so good luck getting it to work...
However, I will say that everything else (aside from not being able to tap the trackpad for clicking) does work fantastic on my iBook SE (first ed., 366MHz, 6GB HD, upgraded to 192mb of RAM).
Classic runs just fine for most programs I regularly use (except Virtual PC, do NOT launch VPC under OS X), and is only slightly slower than if I boot into OS 9 directly.
Back to the Virtual PC issue: I tried booting it once while booted in OS X/Classic environment, and got a message about my OS being unsupported and VPC would now quit. I didn't really expect an emulated environment to work in an emulated environment on beta software anyhow. Everything seemed fine until I booted directly back into OS 9 and tried to launch VPC. Crash and burn, it wouldn't launch anymore, even after many various updates, reinstalls, copying from backup, etc. I ended up wiping my HD clean and reinstalling everything (I had my VPC HD image backed up, thankfully...), never to attempt to launch VPC under OS X again.
(I should mention that it was actually DP4 I had installed at the time of this problem, and OS X PB which I have now, and have not tried, nor will try, launching VPC on.)
But again, for everything else, it looks and feels great. My favorite is being able to force-quit if something goes wrong with a program and not having the entire system brought to its knees...