I've never moved that much data with Migration Assistant, but I've dragged & dropped that much from my internal to my external (and vice-versa) via FireWire 400 in a bit over an hour.
That's why I asked...to maybe put some perspective on what you'll be facing.
It's by no means going to be a terribly long affair, no matter how you do it.
Edit: Qualifying that... My experience has been with my iTunes Library, which comprises about 600 relatively large files; if you're migrating a whole bunch of small files, all bets are off.
Last edited by artie505; 02/26/15 10:00 AM.