If the XM2 and XL2 have shutter speeds go to 1/16000 and Sony to 1/10000 but the intended purchase, DVX100B goes to 1/2000 why the difference?
:undecided
Is there a reason you'd want a shutter that fast? 1/2000 is so fast and requires so much light that it's pretty unusable in almost any circumstance other than direct sunlight anyway.
With 1/2000, you'd need 32 times as much light (yes, 32 TIMES as much) to get an exposure as you would with a normal 1/60th. If you were going to try to use 1/16000 you'd need 256 times as much light. It's not practical at all. It's more of a "bragging rights" kind of statistic, kind of like "100x digital zoom", something no shooter would likely ever use.