I've been running Vista SP1 builds for a while and I like them. I don't like the process of changing builds which is "simply" a case of uninstalling the old build, letting it reboot twice, updating the registry, doing find updates in windows update, reboot, do it again, reboot, do it...
[updated to correct grammar in title - thanks to Warren Jacobi for pointing it out to me] I have been hearing about these at work - I don't have them yet, so can't comment on them, but apparently they will be going to trial soon and then out via updates. 938979 Vista Performance and Reliability...