I prefer Kor too! He strikes me as being more of a pragmatist and seems to have been less indoctrinated than Kang. This is not to suggest that Kor believes any less in Klingon ways, but he strikes me as having a broader mind about the universe in general.
KOR: You'll talk. Either here, now, voluntarily, or under our mind-scanner. The fact is, Captain, I have a great admiration for your Starfleet. A remarkable instrument. and I must confess to a certain admiration for you. I know, of course, that it was you who destroyed our supplies last night.
KIRK: Something was destroyed? Nothing inconsequential, I hope.
KOR: Hardly. They were quite important to us, but they can be replaced. You of the Federation, you are much like us.
KIRK: We're nothing like you. We're a democratic body.
KOR: Come now. I'm not referring to minor ideological differences. I mean that we are similar as a species. Here we are on a planet of sheep. Two tigers, predators, hunters, killers, and it is precisely that which makes us great. And there is a universe to be taken.
KIRK: It's a very large universe, Commander, full of people who don't like the Klingons.
KOR: Excellent. Then it shall be a matter of testing each other's wills. Of power. Survival must be earned, Captain. Tell me about the dispersal of your Starfleet.
Kor is able to recognize that the two powers are not that different in their aims. Add to that, he recognizes the similarities between both species. This is something that Kirk is not able to begin to comprehend until The Undiscovered Country.