1st column: best suited vs. infantry units

2nd column: effective vs. both but easier vs. vehicles

3rd column: Good against both but hard and/or impossible to hit at longer ranges.

4th column: just the advanced engineer, no other categorie to put it under

With this basic knowledge, you would know that... ex: No sense in buying sydney/raveshaw if ur only attacking infantry, then buy havoc/sakura instead. they do around same damage but MUCH less reload time, but do almost nothing to vehicles