Yes, they do suck. I regularly see and help people that are dealing with broken systems because of stalled/incomplete/broken in place upgrades.

Regardless, it's easy to not lose your setup, run the latest OS AND not do in-place upgrades.

Just put /home on a separate partition and you're done. Use dpkg to make a list and restore a list of applications (same with repos). A few files to backup and a few minutes to wait for the apps to redownload. Completely clean system. Same apps. All the while /home was untouched.

I've never had a single issue with the in place upgrades, and no putting home on another partition is not sufficient. Lots of stuff in /etc has been customized and that would need restored as well. I've been through half a dozen or so and they've always worked fine for me.

I find, sometimes, that doing an

#apt-get -f missing

fixes many of these post-upgrade problems. YMMV!