Re: Upgrading to 3.3
Yes, it essentially amounts to the same thing. There may be differences in the file directories, since a new installation won't contain any files that might have been deleted in the new version. But old, unused files left over after an upgrade won't really have any effect anyway. (For example, maybe a background image was changed. In an upgrade, the old file will still be there, but won't be doing anything.)
As for the database, the upgrade script makes structure changes and adds new content or settings, but in principle doesn't touch your site's existing content or settings. (There are a few settings that need to be adjusted in the 2->3 upgrade. For example, wiki structures need to be turned on, as they became optional in Tiki 3.)
But the end effect is basically the same either way you go.
-- Gary