I recently started making scrappy backings and reversible quilts because I am am on a strict "fabric-diet" and won't let myself buy any new fabric unless absolutely necessary until I have my scraps under control, and I've also trying to use up the pile of floppies that have been sitting around unloved for way too many years.
I'm just learning to FMQ, so I don't have a point of reference on whether it is easier or harder, but I absolutely love it! So far my backs and fronts have been completely different, so it's like making two quilts in one, but with half the work and half the batting. It makes me feels o productive!