These pedals feature a simple 4 sided entry. As you can see they shed mud like no bodies business. The weight is also low which is nice. They have a good amount of float in them allowing them to be soft on the knees.
The pedals are not exactly the most durable but this does not take away from the many advantages.
Alternatives to these are pedals such as the Shimano 540 pedal.
Very positive and secure. They work just the same when the cleat and pedal are totally caked in thick mud. Personally I find the float makes them more comfortable than SPDs.
Take a bit of getting used to. Can be tricky to get into.