These Speedplay cleats work as advertised with SP Zero pedals. They are dimpled, so may provide some aero benefit and are a little easier to walk in. They come with covers for the cleat, but I haven't found those too helpful.
The cleats need to be lubricated before use and periodically there after. I use Finish Line Pedal and Cleat lube. It's a spray that goes on wet but then dries. It works perfectly. I did a ride when I first installed the cleats without lube to test the setup and they squeaked. Applying the lube fixed this.
I really like the fact that I don't have to mess with putting the cleat covers on my shoes every time I get off the bike to walk around. I don't like touching the cleat covers or the bottom of shoes with my hands, who knows what germs are on them? Walking around without the covers can be like walking on ice at times and it also wears down the screw heads that anchor the cleats onto the shoes. Also, the Speedplay customer service is top notch. I had an issue with an earlier set where the covers wouldn't stay on the cleat. One call and they sent me a replacement set of covers. The only downside is that the cleats don't last. This pair of cleats replaced my last set, the spring and metal plate snapped in half during a ride after 6,000 miles of use.