It might be a difference in the cleats rather than pedals.
I have Look Delta and Shimano SPD-SL pedals and cleats. The only significant difference is grippy rubber pads on the Shimano cleats. Better for walking, PITA to clip in/out, compared with the Look Delta. I find the Shimano cleats so annoying I'm going to try cutting those rubber pads off a set of cleats. Clipping in is bad enough, but it takes a deliberate twisting yank that verges on twisting my knee to unclip.
The Look cleats have no rubber pads, so they're not great to walk in. But there's also nothing to hinder clipping in/out. Clipping in and out is smooth and crisp.
Some folks prefer it the other way 'round and find the rubber pads on the Shimano cleats make it easier to hook the pedal the first time and clip in.
I also have some Look Keo pedals but haven't tried 'em yet.