Looking at this topic in general way, would you rather be incredibly strong or super fast? This involves the more physical things.
I think I'd rather be stronger than faster because strength is more of a useful life tool. Sure, you may be able to run everywhere but why not take a cab?
super speed i think would be better because a cab is more polluting, not trying to get into global warming, but strength could come from other things like if you were trying to lift something, you could use a pulley or something, but no device or anything could make you incredibly fast, not counting steroids.
It surely would be useful for society if we had a few superstrong people, there might be a lot of jobs to do for them. But personally I would prefer Speed, especially being a fencer Also, koru has a point there, I would have more freedom in moving around^^
I would rather choose speed because you'd be able to finish any task at an instant. Also if a strong person just comes up to you trying to kill you, you'd be able to defeat them by hurtling a small object, like a rock, really fast because Force= Mass x Acelleration, and though the rock would have a small mass, the acceleration would be astronomical. Plus, you would never be late to school.
I would choose to receive the power of Super Strength because it has more use to it than speed. You would be able to break things, pick things up, and crush your enemies. So Duh! SS would be better!