I have a JB 3.3.3 3G. Backed it up normally and it zipped by.
Downloaded 4.0 and now its been 1 hour 52 minutes and it is only at the c in Backing up.
Other threads suggest the br is not super accurate and it will suddenly jump to 95%.
I wonder if I have a combination of a 3G and not 3GS and JB and that is causing the slow down. It is annoying, but I made the choice to JB it.