In my mind, MCI and DEN are a tie for best for different reasons. Both have few delays. DEN is very spread out and takes a lot of walking to get to where you want to go. The trains were the stupidest idea in the world because of the bottleneck and problems created when failures occur. Besides, I'm tired of being bombarded with UAL everytime I go there. I think that one concourse in sufficent, but they always want more and more gates. They're such a pain in the butt. Good thing Frontier is there to challenge them (and give lower fares to passengers like me!). MCI is so much more convenient, but the gate areas are stupid. I was early for my delayed flight last time I was there, but had to wait with my cousin outside the gate area because they only let ticketed passengers in behind security at the gates. They must have had to spend a fortune on metal detectors and security because of the design. It is more convenient, but older and less "cool" than DEN.