Wrowng.
Russians are the ones with the armour and guns, especially higher tiers. I'm talking about heavies now, of course. They're agile-ish but they don't have the speed.
Germans are probably the most underpowered faction, but they combine accuracy with rate of fire. They have the most accurate guns in the game, and on top of that get very nice speed from them. Their armour, however, is insufficient to fight on front lines until Tier 9 and 10.
Frenchies are always the speed. They have very fast tanks with very good guns, and start with auto loader clips already at Tier 5. They can be a major pain, but their armour is like paper. Either that, or their armour is amazing but they have horrible guns and are very slow (up until Tier 5 that's what it looks like).
USA Combines speed with very good rate of fire and quite decent armour. Their chassis armour isn't very great, but they have the guns to counter that. This is the case in around Tier 7+. They also have TDs with turrets, which is probably the most stupid idea in the world and makes their TDs badly overpowered in that game.
I'm mainly talking about higher tiers here