I have the Planet bike fenders on two of my bikes and the SKS chromplastics on one of them. Both are very good. The SKS cost about $10, more but I don't think they are worth $10 more.

The PB fenders have mud flaps. However, the SKS front fender is longer. The Planet bike fenders are easier to mount and remove. The SKS fenders have a more classic look. With the SKS fenders, the support attaches to the fender a bit lower so that it can catch the front of your foot in a slow turn. But with the PB fenders, your foot can still hit the mudflap. The mudflap on the PB fender is kind of too short.