Since I upgraded to 2.5 the "writing lead-in" takes almost 2-4min in some cases, also synchronizing cache takes 5-20min some times, I have gone back to 2.4.4.0 and everything is snappy fast again... writing lead-in takes 50sec max (DVD) and sync takes 2min max
tested with multiple movies/cd's/dvd's
more of a bug report (i accidentally deleted my log files... sorry ill retest tomorrow and upload them)