UG & CS,
Beatriz and BJ have it right, expect a bumpy ride. Whatever you do, don't let the installation team (floorwalkers) go until you are completely happy with your workstation and it's configuration. If the same migration process is used as here at the 'Wood, your Business Unit Point of Contact (BUPOC) needs to be on the ball and keep chasing up all the identified defects.
I never thought I would say this, but come back DAWN, all is forgiven. My group migrated from DAWN onto DII(F) some 18 months ago and we are still waiting for some of our key software applications to be delivered via DII(F). After some 12 years, the DAWN system at the 'Wood was actually quite stable and all our specialist applications ran quite well. Then along came DII(F)! Just wait until you find out how much each call to the SPOC costs, never mind any Change Requests.
Oh, BTW, the intranet is still down "with technical problems", for the second day.