Not completely the same, but we upgraded from 3.2 to Enterprise 3.4.1. Here were some odds and ends that we came across:
- Auto installer brings up a PostgreSQL database, not mySQL - my-sites dashlet doesn't sort the sites alphabetically - my-calendar dashlet takes a long time to load in MyDashboard - if you want to hide the "Repository" button, you can't just follow the instructions in the documentation
Product was internationalized so there is language bundles for all the properties that was not there before. took me a little while to figure out why my changes were not taking.