Ubiquity: always installs grub to the first partition, even if this is not the partition Ubuntu was installed to. This means the system may not boot after install.
Workaround: Set the boot-order in BIOS to boot from the first drive, and in a terminal
Replace sdb with the partition ubuntu is installed to.Code:sudo grub-install /dev/sdb
Other problems: Ubiquity may not allow you to set the Location properly, or detect an internet connection (even though package downloads still work).
Workaround: Adjust location and mirrors manually.
Mounts: after resuming from suspend, authentication is required to mount the DVD drive. Automounts on boot in Xubuntu don't work. Ejecting a DVD via the drive-button is not detected.
Workaround: switch to a different mounter, such as devmon (udevil).
Non-ubuntu related: udisks2 rules prevent certain drives from being mounted.
Workaround: as root, edit /lib/udev/rules.d/80-udisks2.rules and delete all lines from "Devices which should not be display in the user interface".
Thunar: localization error. Non-ubuntu related: removing it gives "failed to execute: Success" when clicking desktop icons or emptying the trash via menu.
Network Manager: Editing a connecting adds a duplicate.