What's your definition of "not too heavy"? I use these on my Swift folder because you can remove them easily without tools, hence the folder becomes even easier to pack. On another (non-folding) bike I have a set of Wellgo platform pedals that like Powergrips just fine, though I expect the Wellgos are somewhat heavier than the MKS pedals above.
I use regular rat trap pedals and stretch a piece of sheet metal over the top for more engagement. I haven't really found the power grips were my answer, but it does depend on what you specifically use for shoes and what kind of problems drove you there.
I found that the regular size strap is way too small if you wear touring shoes or sandles. On the Riv site they make some shot about "Brobdinagian standards -- or around 12+" as maybe being a problem with the regular straps, I'm an 11 and couldn't use them.