Interesting! I've never seen that design before. It must be brand new.
It appears to be the same weight as the 256. I'd be curious to see some different views of the frame, but it looks like this might solve the high-stress problems they had on some 256 frames at the junction of the right and left seat stays before they go to the seat tube.
I hope they improved the cable routing a bit as well.
I still love my 256 and feel no need to replace it, but if it was damaged, I might look into this frame depending on how the reviews pan out.