What are you going to use it for?
I think the 6.5x55 is good for thin skinned game and long range target. The 9.3x62 is a friggin' hammer and is good for hunting all kinds of big game, including dangerous game.
I just picked up a ever-so-slightly used 9.3 Medium Lux, which I plan to take to Africa for the large antelopes. I may even try it on Alaska brown bear if I get the chance. It would also be good for jaguar in Colombia or Bolivia.