i've always...
...done fresh installs of new versions, always hear bad things about upgrading. and i've never had a problem with doing fresh installs...until 8.04 when it broke my wireless (integrated centrino wireless), other than that no problems
my current wireless issues have been resolved, but it was almost a "showstopper" for me to have a commone wireless device not work out of the box (as the last 3 versions of ubuntu have detected and enabled automatically on first boot), oh well