It may be wise to try them as-is with the existing firmware and updating if you have problems. You do always run some amount of risk of bricking drives when updating the firmware. In the case I documented above, I decided to update because the drive was exhibiting strange behavior when closely examined.kryptex, I guess it make sense... I just did not expect so many bugs but like everything else, these components are getting increasingly complicated..
So in other words, before I move my Hitachi's 5k3000 to my new M5016 controller, I should probably flash their firmwares...
A case can also be made for updating firmware to make sure all of the drives match. The big storage companies (Dell, HP, EMC, Netapp, etc) do this routinely with their own custom firmware but in those cases the drive firmware is a component within complete, stringently tested systems with all individual hardware and software components sourced, assembled, sold/resold and supported entirely by one company.