I concur with the others. I just swapped out my metal stock platform pedals on my new trail bike. They managed to cause me to slip a pedal and bash my shin last weekend, but because they had smooth short nubs at least I didn't get cut. Yesterday I put on a pair of Azonic A-Frames and went for a ride, and the difference was shocking (way better). Then again, I also ordered a pair of hardshell shin/knee pads at the same time and plan on wearing them often.
I've had too many injuries as a direct result of shitty pedals, all plastic, and going back to when I was just starting riding bmx and slipped a pedal on the road down a hill. Nice sexy scars on a leg, a arm, and my side, but the infection from the asphalt shards sucked.
Just say no to plastic pedals!