Depends on how big a project you're talking about. It's easiest to migrate, and migrating to SAV 9 isn't too difficult (start with servers and SSC, and you have to uninstall the old SSC to install the new one). If you're talking just a couple of machines, and you're worried about things going awry, uninstall.
Hanlon's Razor: Never attribute to malice that which is adequately explained by stupidity.