So for so good..........
I'm planning on doing a fresh install of Vista this weekend, so wasn't overly worried if SP1 went horribly wrong.
Installation did take a while - and M$ are still incapable of making a progress bar that works - For god sake - how difficult can it be - a progress bar shouldn't go straight from 0% to 100%, nor should should an installation have three different progress bars when one would do the job. A progress bar has one job to do - show the end user how far into a job their PC is, so they know whether to just go make a coffee, or go watch the Godfather Trilogy. /end rant.
When I came back to my PC, everything looked normal apart from some customer feedback spyware doohickey. I decided to copy the 400MB patch onto my backup server, and something weird happened - it copied the file. It didn't spend three hours calculating how long it would take - it just copied in a few seconds. I've just tried the reverse - I copied a 1.3GB file from my server onto my desktop - It instantly said it would take 34 seconds, and it did. That alone is worth the hours installation, as if it carries on working will save me time in the long run. Well done M$ (yes I know it should have worked like that from the beginning but if M$ feel appreciated maybe they'll fix other things too - like why I'm using 1GB ram when I only have Firefox running).
I'm sure there will be horror stories about this patch - And I may well have been led into a false sense of security only to get my head chopped off at any moment, but for the moment M$ still have at least one moderately happy customer.