I've decided to stick to the MTB for the time-being.
As durable as most 700c/27in wheeled bikes are, my paths usually lead through a construction workers trash bin. Nails, splinters from wood, staples, broken windows, jarred pieces of metal.
Not to mention that the wind makes a pretty good workout for those areas where the gym is not going to be. Truck Stops that are segregated from the cities by a hundred or more miles comes to mind.
And I just plain like them better anyway.