The Shimano SPD M-540 pedals provide top end performance at a value price. Shimano SPD mountain pedals are some of the easiest and most trouble free to use. They are easy to set up and extremely easy to clip in and out of with their reliable, predictable action. While intended for mountain bike use, many riders find SPD pedals are the best choice for commuters, cyclo-cross, or even on their road bikes. In short, any time a lot of walking may be required an SPD pedal and shoe system may be the best option.
Four CX races into the season, and the cleats are too loose to safely stay in the pedal, and the tension screws are stripped. See similar M-520 comment about metal quality.