Yes, and no.
The US Army, overall, is one of the strongest as you have a very large Army, with loads of equipment.
However, if you are looking for the best fighters, no. Man for man, the US Army is okay, even good, but, many others are much better. Canadians, Aussies, Brits, the Gurkhas (probably the best fighters in the world), and many more. But, while quality counts, so do numbers, and the US has the numbers, and the equipment to do well. But, a company of Americans against a company of Canadians? My money's on the Canucks!