i dont waste the time verifying either. i have unchecked [U]Delete temporary files when done[/U] this way if the burn is bad i can reburn it later and manually delete the dvdfab output after i have watched the backup dvd.
verify only checks if the burn is readable, not if the rip is good. the rip can be horrible but if the burn is good then the verify will pass.
as to why the verify takes longer i have no idea and will not try to find out.