Thought I would start a thread to gather info on what method(s) work to upgrade from 3.5.13.2 > R14. I did this from konsole in an x session.
System: Debian Squeeze LTS, AMD64. I changed my sources list to the nightlies. Ran "apt-get update". There is one package to be removed, many new packages to be installed and fewer to be upgraded.
'apt-get upgrade' will not install the new packages, they are held back. I used 'aptitude upgrade' and the resolver figured out all the depends, new installs, upgrades and removal.
Almost perfect, better than any previous upgrades. A couple of things I noticed is my desktop wallpaper was set at the default, I like 'alien nights' :-)
Ending my current session via the logout dialog drops me to a cli, I have to 'restart tdm-trinity'.
I did test this on a vm (cloned) I have for legacy support purposes. Real hardware may be different.