Release Candidate 1 for Windows XP SP3 has been released to the public, available here
As I have only had this service pack installed for a single day I am not too sure if I’m just experiencing the Placebo effect else my install does feel faster… (Reports said, when the first Sp3 beta was released, that there was up to a 10% increase in performance).
Overall, if I didn’t know Sp3 was installed, apart from this performance boost (assuming it’s not Placebo :P), I wouldn’t have noticed any difference between SP2. On the hotfix side of things that means no more excessive updating after the Windows install of a slipstreamed sp3, for now anyway.