Tom Clancy's EndWar/Units

Units intro
What you'll be using to attack the enemy forces fall into a few categories: tanks, APCs, gunships, riflemen, artillery, engineers, command trucks and drones, which forms a combat chain; tanks beat APCs which beat gunships which beat tanks. Engineers also beat all vehicles in cover which is beaten by riflemen. Artillery beats everything in cover or otherwise on the ground as long as it isn't in range to attack the unit itself. Lastly, command vehicles are equal against everything but don't do well against anything.

Unit breakdown
There are differences between the factions which break down like this: Russian vehicles tend to move slower but have more armor and firepower. European vehicles tend to have less armor but move faster and are more accurate. American vehicles are somewhere in between in terms of armor and other factors. The real difference is unit special abilities which have many layers of usefulness.

The best special ability is the HESH (High Exploive Squash Head) which in turn becomes the BLOS (Beyond Line Of Sight) simply because it has an area of effect attack which can damage many targets. Next is the Vindicator simply because of its attack speed. While the flamethower can and does take a few seconds between activation and hitting the target, which is often the difference between living to fight another day or being sent to the junkyard. The uses for the tank special abilities is pretty endless. The best time to use them is when you need to kill something in hurry (i.e an artillery piece waking your units across the map or a barricade).
 * Note: HESH evolves into BLOS.