Speedplays. 1) extremely light; 2) unlimited float; 3) very steep cornering angle;
4) impossible to inadvertantly pull out of in a sprint (which does happen with some other pedals particularly with worn cleats)5) two sided, ease of entry.
The knocks on speedplay are 1) too much float, and 2) allegedly small contact area. Most people riding them get over the float issue in a couple of rides, and if you don't there are always speedplay zeros with limited float. The contact area issue I think is a red herring. With a stiff shoe it just doesn't matter, and besides the effective area of contact , the pedal and the cleat together is bigger on speedplays than most pedals.
The best endorsement for speedplays is that very few people that ride them change to other pedals.