No 10.3.3 problems, "muting" problem fixed
I've been using 10.3.3 for the whole day on several Macs - a dual 2GHz/1.5GB/320GB G5, an 800 MHz/512MB/80GB 17" iMac, and a 400 Mhz/320MB/6GB Lombard G3 PowerBook. Primarily, I've been using the G5 (need to enjoy it before, in a week or three, it becomes one of the "slow" G5's), but I've played around on the other two as well. I shut all three off completely to check out cold booting, and no problems.
I've seen no problems, either during or after installing. My firewall was still up, my autofill worked as before, etc. None of the other problems reported by others was visible to me, although I've done no Samba-related testing. I'd like to say that things feel faster, but I have no hard numbers to back that up with. Certainly, nothing seems slower. Halo seems OK, but I only played with it for a few minutes, and that might not have been enough time.
My "professional" programs (OmniGraffle Pro, Office, etc.) all seem to work fine.
One thing which was fixed and not previously noted (perhaps I was the only one with the problem?) is that muting once again works for me when I'm using the optical digital out on the G5 - 10.3.2 (or was it 10.3.1?) broke it - the muting (via keyboard or GUI) had no effect on the digital out. Now, though, it has resumed working correctly.
Overall, I'm very happy with the update, at least for now (I seem to have been lucky so far, so I expect to wake up to find that my hard drives have all melted or something).