The CD's and DVD's can be scratched. The HD-ROM is made of metal so more durable. Seek-time seems to be the magic question, there are many numbers out there on how much faster one type seeks then others. Tape drives are obviously the slowest since they require rewinding. Among the rest seek-time is not specified.
Versatility is the main equalizer among drives.
DVD is currently only writable by the company, but removable. HD-ROM is writable by the user once only, and not removable. I haven't seen any bench-marks but the media claims are the holograms beat all of the other mediums in all four areas. This of course is way offset by their enormous price. More servo type information will be included to increase density of floppys.