I've got a rigid MTB w/ slick tires that I ride for running errands and for fitness. I've got some Shimano M545 pedals which are steel-caged double-sided SPD pedals and are rather porky at 567 grams.

Given my admittedly pedestrian usage of my bike, which includes few hill climbs which are steep but only a few hundred feet, would I benefit from some lighter, cageless SPD pedals? I was looking at the Shimano M540's which weigh 350 grams. Can one "feel" a difference in pedaling effort and power transmission in an application such as mine?