I'd play but my concerns are a blend of everyone elses.
Physics wise, it's not making all that much difference upping the FPS by 100 with the same bb's right? So serious injuries and such will be pretty much the same.
But douchey close rangeness is my prime concern. I've taken some auto bursts from point blank before and damn if the injuries didn't last for weeks and actually leave some scars.
There's always the spook factor too. Seems I can't be my quick, sneaky, unexpected self without getting a shot to the head by someone with an itchy trigger finger. If I pop up on someone unnexpectedly it seems I scare them and they shoot first, appologize and ask questions later. That or are so despirate to shoot me, I take like 50 in the stomach before they're satisfied. This will be less pretty than it already was with higher FPS's.
Secondaries should be a MUST though. No execptions. No single shot compensation. New gun entirely. Use at closer range manditory. If you don't have it drawn, you don't shoot. Doing so anyway would make you a flaming piece of shit.