If you find yourself without alsa audio in gutsy after a fresh install or upgrade.
There are two methods one involves moving the files .asound.rc and .asound.conf from out of your /home directory and rebooting to re-enable alsa.
The second method is fire up your terminal
use list to see under what name your sound card is listed then select it as the default audio device and finally reboot for the changes to tak effect.
asoundconf set-default-card <your card here>
Finally i think the people who are having toruble seem to be the folks who have customized their systems or do lots of compiling.
If your system only installls software from the repos then i guess the upgrade should go smoothly but if you are constantly compiling etc then it probably won't.
At least that is what observed from hoary to dapper my upgrade went smoothly, once i was comfortable with compiling stuff i have done it for every version of ubuntu since then and the upgrades never work properly from dapper to edgy via upgrade never worked correctly for me. Since then i only do fresh installs its a pain to re-add the compilers and dep files all over again but it would be even worse if it was done via upgrade as this experience once more has taught me.