I know it is very likely Apple's fault but...I hope you can give me some help.
I recently bought a Mac Mini (no optic drive) with 10.8.2 and kept the rest of the FW800-400 chain. The last of the chain is a LaCie DVD drive that used to work perfectly with the old G4 MacMini with 10.5.8
A complete resumé of all troubles can be found at:
The latest is, when I try to burn a data DVD with divx (.avi) files in ISO 9660 format, it seems everything works fine, but at the end I have something unreadable for my Pioneer DV696H player (perfectly able to read this kind of discs, otherwise). When I try to read the disc content from the Mac finder, everything is slow, not to mention the preview thumbnails creation or opening.
Tried with Toast 11.1 (1072) and with Burn 2.5.1 as well.
I think Apple screwed up something in FW management with 10.8...but until now no clues from nobody