I have Egg Beaters on my road and mountain bikes, accumulating over 1,600 miles on them so far.
Egg Beaters are lighter than virtually all road-specific pedals if you consider the cleat as part of the weight.
For MTBers, mud-shedding ability is amazing.
I also found clipping in slightly more challenging at first as tension is not adjustable and clip-in resistance was more than I was used to.