I'll do what I did with Panther, see how other people do and upgrade one of my machines and see how that goes.
With Panther, there was a few issues that cropped up from the upgrade (no matter how clean your Jaguar installation was) that caused me to do a clean install on all my machines.
Tiger may just be an upgrade for me or it could be a clean install. I won't know until sometime after I do the first machine.