Your user data will migrate automatically from the UM1 DB to the UM2 DB, so there is no reason to export/import data. The challenge is that there is no way to migrate a deprecated user role or custom email settings, etc. into the new UM2 environment because they are handled differently in UM2. That you must do yourself after the update. Remember also, that you should disable UM extensions prior to the update, and remember to also update the extensions afterword.
Of course there were bugs with the new release, but some of the problems were not bugs at all. Most of my problems were merely surprises, because I was not aware I had to also make changes in settings after the update. When things did not work, I did not know I could fix them myself with simple changes in the settings.