The crashes I was referring to were seg faults, which happened seemingly at random, several months apart. If I had more useful/reproducible info I would've filed a bug report :(
The unclean shutdown issue that I saw in the changelog seems to be https://github.com/martanne/abduco/issues/5
Before switching to dtach I was working around this by deleting stale sockets in my .xsession file:
http://chriswarbo.net/git/warbo-dotfiles/commits/b182acaa1dc...