Rodguy1 - for most of us homebuilders our time is free. The one thing that appeals to me with the roto-zip process is the idea of cutting all through at one time. Where as the 'traditional' way is a top and bottom cut and then a slice of the plastic. From an outsiders point of view (I've never cut auto glass), that seems to be a lot more chance for stupid mistakes ending it badly. Maybe the same chance for failure is there either way, but if it comes down to time over risk, I'd rather take my time.
I may give glass cutting a shot because I just like trying everything, but odds are I'll wind up going somewhere. And if I do try myself, I'll be asking you for direction. Personally I can see myself trying to go a little to fast or taking a little to big of bite and then ... FAIL! I know how I can be.
EDIT: Oh, and thanks for posting that link. I'd never seen that tech before. Good stuff!