I haven't used it. But the Sync problem has been experienced by many folks in XP also. So far, I don't know of a definite fix, but it appears the problem has now migrated to Vista. All I might suggest here is to watch exactly how the files have been encoded to see if you can pick out any difference as far as how the audio sync is handled. If you find one that works correctly, let us know.
As far as the frame rates, Nero will lower the quality to fit the video on one disc. If you have plenty of room, it should maintain at least the original video quality unless you have some custom settings in place.