I prefer the round ones.....
I had the P-zero on my 50i and loved them, but right now I have the non run flat michelin power sports and enjoy them. Honestly for how many times my wife have used the run flats (without spare) I enjoy the piece of mind. I cannot comment on comfort of the power sports since the x5mc is stiffer to begin with. I would have bought the P-zero again if I had to replace them for sure.