we are veering off topic, but ime ss is vastly superior, just as quick up the hills (if there are dead spots, one should improve the pedalling technique), you can descend any long hill in relaxed manner, without a speed limiter, in a very aero position (=much faster), bunny hop over obstacles easily. safer in case of unexpected situation on the road. it's very reliable too, no problems with good freewheels in my ~14yrs of riding different ss bikes. my "summer" ss bike is light enough with two brakes - 6.55kg without the w.weenie parts.
fixed bikes belong to velodrome, too many compromises/drawbacks for the road use.