To give you complete picture I don't actually stay and look at the screen waiting for it to finish
I turn it on, it says 1 hour left or 2 hours left and I go to lunch. It runs pretty consistently so my guess is the time shown is somewhat accurate.
Anyway - whether it is 30 min or 1 hour - the point is the migration wizard is running pretty good now for stock stores. Still few hiccups to take care of - as outlined by me earlier - but in general it works ok.