I use plastics on my cheapy commute bike, platform style bmx pedals. When i pedal too far into a bend and strike the pedal on the ground, they tend to grind the edges off rather than try to kick you off the bike.
There's also a new generation of plastic pedals with inserted rows of aluminium spikes - lightweight, cheap, grippy and funky colours. I expect loads of people are branding them, but Gusset is the first one that springs to my mind.