I recently did a similar switch, going from a 52/39 setup to a 52/36 semi compact crank. My new crank is a 4 arm Chorus Ultratorque 11 speed crank. Shifting is even better that with the previous 10 speed Ultratorque crank. The big advantage over the previous 5 arm crank is that there is no longer a need to buy a whole new crank to switch from standard to compact setups, all you need to buy are the chainrings. As well, you can buy replacement chainrings not only from Campagnolo, both Stronglight and TA make chainrings to fit these cranks