No, there should be no real difference except maybe some compatibility issues (Motherboard maybe)...

Some reported massive Performance gains, some reported mild performance gains, and some (including me) reported : nothing really changed...

Personally, if there are no unsolved issues or Problems with the Card, I see no reason to flash the Bios of the Card. But that's technique only, many people just like having the newest Bios Versions on their cards...

Greetings
FalconFly