I use regular SPD pedals on all of my bikes because I like to be able to walk in my shoes (no roadie duck walk) and I am in a large metro area where I often have to clip in and out. And my knees appreciate the few degrees of extra float.
I am fine with the single-direction release cleats, and find them easy to get in and out of. The multi-directional release cleats pop out too easily for me.
Am I losing some watts to the pure roadie SPD-SL? I can't tell. My shoes are pretty stiff.