Looking at the people who moved to FF3.5.0 yesterday:
- 65% downloaded the FF3.5.0 installer and installed from it
- 35% manually did Help->CheckForUpdates
That is a large percentage of people doing CheckForUpdates.
Considering this was our first time having Major Update available on release day, and considering there was no user prompting of this new major update ability, I found these percentages quite delightfully stunning.