The best answer is 737. Why? Because we have a bunch of them and that means more opportunities.
Now some took the debate to other areas.
Training. It seems there is almost universal agreement, UAL 737 is at the minimum level required by the FAA. It should be getting better as things move to Denver.
Cockpit. Airbus by a long shot is better.
Which is more quirky? It used to be the Airbus but with the -900 and "Max" I think it's a tie now.