On paper, Davis is the stronger of the two men when it comes to his biography and experience a candidate for chief executive. Davis grew up in a farming family, was sent away to school and then to West Point, and spent some time in the army. He got married and moved into plantation life, but then his first wife died. He spent a number of years out of the public eye before serving in the House, the Senate, as a Colonel in the Mexican War where he was wounded, and then Secretary of War under Franklin Pierce before returning to the Senate. I think his main weakness was his temperament. He was just not someone suited to the interpersonal demands of the Presidency, something he and his wife Varina apparently recognized. But he was a man who believed that when his state or his country asked him to serve, he should do so, so he took on the job of CSA President as asked, and did the best he could.
On paper, Lincoln was a lawyer with a poor upbringing who had limited political experience. But he proved to be someone who was determined and who would stick with what he believed, and who was willing to push enormous social changes to win the war and preserve the Union. Lincoln is not a man I think very highly of for a number of reasons, and I think his assassination made him a saint, whereas if he had lived we might well evaluate him differently, but there's no denying that he made several bold leadership moves of a sort that Davis never did. Lincoln was willing to transform society to achieve his goals, while Davis's goal was to try and preserve it as it existed. That may well be the main distinction when it comes to leadership style between the two men.