What kind of difference? You'll notice your bank account balance shrink a bit, and you'll have more shoes in your closet. That's something.

I ride SPD pedals, because I ride out to some incredibly scenic places, and occasionally like to get off the bike, walk to a different vantage point, fill my water bottle out of a mountain stream ( I have a purifier ) and the like. I used to get painful hot spots on parts of my feet, because my shoes flexed too much. I got a pair of carbon shoes, but kept the SPD pedals, and the discomfort went away completely.