All is well with me... I've shot and cut another short in Tiger and all went very well. I've also opened and messed with older projects without any troubles.
SAYING THAT...
I did a clean fresh install of EVERYTHING on a seperate drive. I still have Panther and ALL my proaps on another drive I can boot from if needed.
I wouldn't recommend doing an overwrite install of Tiger unless there is NO other way. Too many things have changed and I'm afraid it will trash something you don't want trashed.
Don't do it mid project! Too many chances for error.
The new AUPitchShift audio filter that shows up when you load FCPHD is worth the upgrade to Tiger!! Something to do with the core audio update.
I decided i would WAIT. been getting a few emails from 3rd party companies indicating i will be much happier if I wait. however, i'm doing the upgrade on my non-critical mac, soon. geez, the "prep" feels like it takes forever. looking forward to it though.
Mpeg2s work the same for me. Though I find h.264 (what I like to put on the web now) is much better inside FCP. I don't have the control over it like I do in the new core video shell that FCP uses.