Old question, stumbled upon it.
It would be my opinion that the higher voltage could allow you to fall into an NEC category that will require more safety equipment and a different insurance classification making it negate any advantage one way or the other...
I believe as of right now the UL provisions limit US systems to 600VDC and the NEC 690.7(C) does not have the verbiage for use yet.
We always seem to be 5-7 years behind Europe.
GT