I agree, you can't tell for sure until the careers of both are over.
But as far as clutch goes, you have to go with Lebron. Maybe last year Kobe would have been my pick, but he was to inconsistent this year, and Lebron got more and more clutch as the season progressed, finishing it off in the top tier of clutch performers in the whole league. Kobe definitely got better too, but he was a step behind Lebron, in my opinion.