I've talked a bit about some issues in the latest Intellipoint release on Vista. One issue that some people had reported and that I definitely experienced as well was that Intellipoint prevented the screensaver from kicking in unless the workstation was locked.
A few days ago I saw an optional update on Windows update for "Microsoft - Other Hardware - HID Non-User Input Data Filter" and installed it. I'm not quite sure what it did, but I'm happy to report it seems to have fixed the screensaver issue.
Now, if they posted an update for the vertical scrolling speed issue (the one where the scroll-wheel vertical scrolling speed randomly resets back to it's lowest speed), that would be awesome.