Of course I'm pro American, but the Wehrmacht were superior in both training, and most weapon development. if they didn't fight a 2 front war and were not outnumbered, they could have defeated the American, British, or Russian armies
The Germans were superior in quality to any other participant in WW2. But If you ask me which of the two would beat the other however, I would go with the US. America had fresher troops, more supplies, and a larger force. Back then, quality could only take you so far.
This is kind of difficult to determine as both groups had their forces split (70% of germans on the Eastern Front and about half of the US army in the Pacific). Also the British were also on the same front as the Americans. Both sides had advanced weaponry (Standard issue M1 grands for US, STG 44s for the Germans). ultimately I would say the US would win but it would be a hard fight.