1.Armor (a.k.a. the "No need to tech company): Five reasons:
1.Demos
2Demos
3.Demos
4.M10s
5.The bulldozer which surely isnt as bad as people claim, just a bit overpriced
2.Cavalry
Short range friedly areas will embrace a great properity under the rule of mighty rangers while long range friendly will witness the terror caused by Pershing (which is a bit overpriced, but good) Dont forget to put mines with your rifles
3Mechanized
One simple reason: If you put your rifles into the jeep and use it effectively, plus get lucky enough to avoid raketten, the game can be over in 6 minutes (only against OKW)
