To be broad you are looking at the game as a puzzle to be solved instead of as a real and therefore faulty and complicated issue. In other words you are in the game instead of above it. To give some examples Colossus Smash is by far the worst of the three and shouldn't be recommended, Shield wall is really good against Valla and Glory to the Alliance is by far the best value/effort choice and most broad one, therefore the best choice for guide like this. To explain something in between,...

It's bad. Details don't matter when you don't know what you're talking about.