Just did a full update on my Debian etch13 without any probs
Regarding The long waiting when preparing files, i guess people just have to start the update and go make a cup of coffe instead of panicking
It quite logic that the more sites you have the longer its gonna take the system to compress the backup.
So either sit and stare at your monitor for 5 -> ~ minutes or learn to drink coffe
And be happy that it makes a backup, i bet it would be worse if something went wrong (wich it newer does) and no backup was there