I have both the MKS RR-2 Quick Release Road Pedals and MKS FD-2 Folding Alloy Pedals (
here), both of which I used on a Bike Friday and now on a Brompton.
Of the two, the quick releases are lighter and elegant, but it is a pain having to pull them out every time you fold the bike (if you want to pull them out). The folding alloy pedals are wider and heavier, but I bought them because they're about the only folding pedals I've seen which accept toe clips. The only downside, besides the weight, is that I had to do quite a bit of drilling and sanding to get PowerGrips to fit which I prefer over toe clips. But now that it's done, I'm pretty satisfied with these folding pedals.
A couple other issues to consider, however: the cylindrical portion of the pedal lock sticks out because it can't fold, and when the pedal is folded, there is no friction preventing the pedal from swinging back and forth.