You are mistaken about #1. 'apt-get dist-upgrade' is for upgrading your existing release, it does not upgrade you to a future release. (It can be used to do so, if you edit your sources.list first, but this is not the recommended Ubuntu method for some reason.)
Ubuntu is a somewhat buggy distro (including the upgrade mechanisms), and as a result many users experience failed upgrades. My experience on UbuntuForums is that the risk of failure is directly proportional to the amount of third-party software, PPA's, proprietary drivers/modules in use, etc. ("Vanilla" installs are most likely to successfully upgrade.) If it's a production machine, it's always prudent to test the upgrade on an identical spare machine.
Last edited by snowpine; 01-30-2013 at 11:19 AM.