I have the double sided shimano A520 spd's that i originally used on my hybrid. I took them off and put them on my road bike when I purchased that bike. Given the choice, I would rather ride clipped in however, I like the versatility of being able to wear tennis shoes, sandals etc when I am just goofing around.

Eventually, I will buy single purpose clip less pedals for the road bike and put the A520 spd's back on the hybrid. Clipping in and out becomes natural.

I won't bore you with the reasons why i like them better -- its not some esoteric or nuanced reason of improved performance or any other bloviated reason that I can think of.... , it is just a better feeling having the feet locked into a pedal.. ... it just feels good.