Nexus 9 (Hopefully) or Nvidia Sheild Tablet?

Hi all, first of all I hope this is the right section (forgive me mods and admins if not.) Secondly I'm looking to buy a tablet running Nvidia hardware for their optimized games and since I'm a Google fanboy the nexus 9 is at the top of my wishlist. I was just wondering as far as hardware goes, which is faster? I know they have the same processor and gpu but the nexus 9's is 64 bit which will make it the winner right? Also is the nexus 9's Kepler GPU on par with the Shield tablets Kepler GPU, and does the Nexus 9 have all the optimizations and benefits of the Nvidia Tablet?