I haven't ridden a Street, but I've sat and made vroom vroom noises on one many times in a showroom.

There's no doubt that the seating position is a bit more aggressive, particularly the rearsets, which are quite a bit further back than an FZ6's. This places my knees on the very bottom of the sides of the gas tank (I'm 5'8). My upper body/arm position seems to be about the same as the FZ6, particularly since I swapped to the FZ6R bars.
The 'new' Street with the new-style headlamps looks alright...I could get used to it. I think the new-style headlamps makes the little flyscreen look more a part of the bike, btw, than the old round headlamps did. JMHO.