Speed vs Strength

[AkumaTh]

It's not the size of the dog in the fight, it's the size of the fight in the dog. 
~Mark Twain

Like everyone said, its pretty much depends on who is the Strength and who is the speed.

Let's take Tifa for example. She can pretty much KO an average person with a single punch. But she can't take a lot of punishment herself. 

• If she were to take on an average opponent with speed proportional to her strength, Tifa would most likely win. A good punch would deliver if they don't know how to use their speed effectively.
  
• If she were to take on an average opponent with the speed of the Flash, Tifa is not going to win. If she can't touch her opponent, she can't really be as effective.
  
• If she were to take on an opponent with a slightly higher speed but the ability to take her punches, there is a good chance that Tifa could lose because the speedy person can take shots and possibly give enough to take her out before they are KOed
  

And that's not including other aspects like experience, knowledge and personality. A cocky speedster leaves openings for a slower opponent. A tactical muscle can realize their weakness and compensate for it. A knowledgeable speedster can use their speed to the most effective. A Muscle Head can make a lot of mistakes. Heck, I've seen stories where the combination of muscle and speed wasn't enough to overcome the other's tactical mind (Sonic Universe #2 with Gamma and Omega being a good example). 

There is no definitive answer for Speed Vs Strength. It only matters if one is beyond comprehension over the other.