I've been running a 5.5 for some time. I wanted to upgrade to 6.0 final on new hardware. I found the upgrade process frustrating; so given there are only a few users I decided to do a fresh install and manually recreate everything I could. I booted the cd on the target hardware and it sensed a prior install (from the failed upgrade) so I selected 'more options' and 'install' expecting to get a fresh install. On reboot I saw that I had the mysql horde password problem so the install did not give me a fresh install. I wiped the drive and did the install a 2nd time and that seemed to work.
In summary, 'install' under 'more options' doesn't do everything it should.