I do neither: I use platform pedals without clips. I used to use Power Grips but they don't work well with some of the shoes I now like to cycle in. For my tour this summer I used MKS Promenade EZ quick-release touring pedals on my folding bike; they're not terribly grippy, but they grip well enough to keep my feet secure. On my bike at home, I use touring cage pedals with somewhat more aggressive spikes, though I have used MKS Lambda (AKA Grip King) pedals in the past and may give them another try.

I've used platforms and sneakers or closed-toe sandals on rides up to 200K. If my feet were less oddly shaped I might use clipless pedals and shoes but I've never found a pair of cycling shoes that really fits me well; the ones I have tried end up leaving my feet numb in places. I did a brisk 35-mile ride Friday with a couple of guys who were using clipless, and I didn't have any problem keeping up with them. I was wearing Keen Newport H2 sandals, which grip the pedals well.