Vera Lite to Vera 3

I have brought a Vera 3 to upgrade my Vera lite as I am having memory issues (Changes not saving, Lots of reloads, Unstable, Scenes sometimes not firing correctly, schedules back to front at times etc…)
My Vera lite is running Ui6 as that is what it came with when i first brought it, i tried to upgrade to Ui7 about 4 months ago but it was a disaster so i quickly reverted back to Ui6.
Everywhere i have read says to move from Vera lite to Vera 3 i need to backup zwave network, then backup Vera , power off and power up Vera 3 and restore back up which seems pretty straight forward but i just have a few questions.

  1. Can i be running a different firmware on the Vera 3 to restore backup or does it have to be on Ui6?
  2. Is Ui6 the same as Ui5 if i am in advanced view or has it got more bugs, I am just wondering if a few of my issues are related to Ui6 not just low memory and should I start the new unit on Ui5?
    3)Is Ui7 still unstable or has it improved in the last few months and should i reconsider this?

Cheers