The Good: Adjustable tension, easy release.
The Bad: Do not work well in nasty conditions.
Overall: For the first timer with clipless pedals, something from Shimano is a must. Having the adjustable tension is key to getting really comfortable with getting in and out of the pedals. The price is reasonable, and they last pretty well. I've raced these on and off for DH for quite some time. I've been reasonably happy with the durability, and if you are not racing in the mud, they are really reliable.