I find that riding a SS is inherently inefficient, which is a good thing IMHO. My legs are far stronger than when I was doing multi-gear commutes, and I credit that almost entirely to SS riding. When I go out for rides on my geared bikes, I'm able to hold a higher gear for longer, and summon a bit more power to get over obstacles. The maintenance issue is unimportant for me, as I barely do any maintenance on the geared bikes. Hauling cargo can be painful, but I usually just tough it out.