Okay USF does get free officers with teching and doesn't require building construction and the associated costs, fair point.
For what it's worth I'm climbing up the 3v3 ladder with USF atm and this is the most usf I've ever played. Riflemen are very good but Rangers are the real stars. 1 thompson and 2 bazooka squads are super powerful, the Pershing is insanely good and you get a lot of value out of units like 50 cal, Stewart, M1 mortar and the almighty Jackson.
Try watching a few high level USF games and see what builds work for them and how they use the units.