I don't think you can say. Sure, Kingsford is going to burn longer than some cheap lump that is not packed in the charcoal ring well, but a good lump packed well in the charcoal ring could burn longer than KBB. There is just too much variation in the equation to say for sure. However, if I wanted the longest possible burn time, I would get the best, most dense lump and pack the charcoal ring very tight and very full. There may be a briquette out there that could be in the same ball park (Stubbs?) but I'd go with lump.
As a practical matter, I can get 15 hours with either so I don't really think it matters.
The best charcoal I have ever used is an extruded coconut shell product called Kamado. I don't think you can get it any longer but when it was available, I split a pallet with a few people. Filling the ring with that stuff could get you 24 hours - no kidding. While it was fun to buy and use, as a practical matter, as I mentioned above, it wasn't worth the trouble since I can get what I need out of just about any fuel.