I’ve updated 3 machines now, a 2-3 year old MBP, a 2 month old Macbook Air and a 3 year old iMac. For some reason the MBP took several hours to re-install (even though the progress bar said 39 minutes). The older iMac took about 30 mins. All the downloads were really slow and happened over night.
Only problem I’ve got so far is the Mail client will no longer connect to my email provider, but I’ve not had time to figure out why…..