Even once they arrive they can spend hours twirling around on the same spot. Naturally this makes accurate skirmishes with the enemy nigh on impossible. Rather than taking the enemy out at a distance until they close the gap, your troops will rush in and take as much damage as they possibly can. The unit AI is also somewhat suspect. Arm your vehicles with mini-guns and because the weapon doesn't shoot 'over' friendly troops, it'll try shooting through them, which causes damage, and if you don't notice in time, it'll also cause a lost unit or two.
Units also make a strange choice when faced with a wall and a gun turret.
An enemy tank rolls up. The turret starts shooting at the tank, and then the tank starts shooting the wall. You soon figure that all you have to do is place a few walls by your turrets and watch them mash the living daylights out of any enemy tank foolish enough to stroll along. Had Thandor come out at the same time as Total Annihilation over three years ago it would still have been outclassed. Today, it's eminently second rate and becomes hard to recommend to just about anyone.