Once you get to the group of cutters that are generally acknowledged as among the best (Palio, Xikar, SAK, etc.), the best cutter is the one that feels best in your hand. All 3 of the ones I just mentioned feel and work very differently from each other. Try to use them and then make a choice.
This is some SOLID advice. I have a couple Xikars, a Palio, and a few others. Of all the ones I use, I go back to my Perfect Cutter or my Xikar ZX Ultra-Slim because in my hand the way they cut seems to give great results the most consistently.
If you only want to buy a cutter or two, I'd recommend trying other folks' cutters to see what feels best.
EDIT: Hah, just realized the post I quoted was from two years ago, not four days ago! That notwithstanding, this is advice I'll be giving to others from now on, because it's still true!