I've been riding an original Power in 143 on my Cannondale Evo for about 2-3 years and love it (over 10k miles on it). I just bought a Canyon Ultimate and because I'm keeping my Evo (at least for a while) I needed another comparable saddle. I decided to buy the Power Arc (143) and just rode on it this morning (25mi/2,400ft). I can see where it is a little more rounded at the seat 'wings' where my inner thigh would normally touch. But generally felt about the same as the Power. It's about 1-1.5mm shorter than the Power as I measured them side-by-side.
I have 30 days to return/exchange at my LBS but at this point it seems fine. Will see what a few hundred miles feel like over the course of a couple weeks.