SPD Clipless
I like that my foot will not slip off if I step in gunk or wear smooth shoes. I personally find no difference, after learning to use them and getting used to them, in my ability to get a foot on the ground fast. The learning for me took only a few rides.
People are surprised I use them with my son in his seat also and the people who are surprised are experienced riders. I think that if my foot slipped off my pedal with my son it would be far worse when I lose balance; so I have one less thing to worry about when pedaling.
I did miss a clip in at a light today and had to pedal through the intersection with a weird position until I was able to get in properly. But really it was not an issue, just an annoyance.
In the end it is a comfort and personal preference decision.