I've used both Crank Bros. Eggbeaters and MKS platforms/clips and leather straps and here's the benefits of both that I personally have noticed.

With clipless, connectivity with the pedal allowed for faster spinning and more flexible control on back-pedaling or skidding.

Having become comfortable with clipless, I then swapped back to clips and found that the extra movement allowed and the quickness in which you can put your foot down are very nice. Learning how to quickly get into clips doesn't take long once your balance becomes better.

Other than that, it's really a toss up. Currently I'm using clips, but that's due to the fact my shoes are just giant ventilators and I can't keep my feet warm worth a damn. The extra feel given by them is nice, but with a good cleat, clipping in provides the greatest connectivity with the bike.