If I may The USA race that has been introduced is i think the best way to learn the game. However you do realize that they are dependent on using infantry to their fullest and using their Armor in a cautious manner and striking or reacting to your enemy's armor. AT guns an Pak guns for the US are AWESOME! And of course Air Borne

in field AT gun call in if you can hold the line.
USA= Ability dependent, not great armor of infantry in a 1v1 fight but the BEST race (imo) if played right. I like to think of them like the Eldar of CoH2 honestly but with mines and stuff.
German (vanilla)= Epic Armor, decent artillery and MGs, infantry is also very good, but upkeep on all units is high. Infantry numbers are low.
German ("Spec OPS")= idk really. But they seem to depend on early game the set up shop. Interesting race, with high veterancy (levels).
Russians= Decent armor, artillery is epic, their flamers are epic, Molotov are epic, Guards Infantry are you best friend.
My very simple thought on each "race"
"...With every strike of his sword, with every word of his speech, does he reaffirm the ideals of our honored master..." -From the Teachings of Roboute Guilliman as laid down in the Apocrypha of Skaros. Space Marines Codex pg. 54