Kendrick, it's not even close. I can understand why you'd prefer Drake, but you'd be wrong.
Critics will mention the voice but I counter by saying Kendrick performed his records 1000x better than Drake did and overcame that disadvantage to claim the throne.
Lyrically, the first part of 6:16 is tougher than most of Drakes timestamp series.
Kendrick's battle bars were better, the flips and entendres had RapGenius busy.
Drake is a great spitter/front man. Smooth and clear delivery, packaged with amazing production. It checks all the boxes, has bars for the hip hop heads but dumbed down enough for mainstream mass appeal.
In that sense he's the epitome of traditional commercial rap, and he does that at the highest level.
Drake a snapshot of the past. Very much the easy listening and smooth delivery of raps from yesteryear.
Kendrick on the hand presents as a writer/recording artist first. It's always been substance that appealed moreso than the style.
Despite this, he beat Drake out with style.
Kendrick is like a snapshot of the present where he has more artistic expression with his raps and music overall reflected elsewhere by Kanye, Future, Thug & Kodak.
That coupled with technical intricacies musically and abstract/free flowing thinking evident in his lyrics (influenced by Wayne, Andre3000), you can see how it can be a challenging listen to some ears.
I appreciate both, and both are needed for genre diversity but I cant really rep drake since his bars are not his.
Kudos though, they sounded the best they have in years but theres gulf between the two when it comes to talent.