In terms of training and equipment, particularly weapons. I'd guess that the British Royal Marines used the Snider–Enfield, and perhaps the French the Chassepot, although I have my doubts. But what about the US? And were there any notable differences in their training and tactics noted in the history books?
Actually, as a follow up, how did US, French, and British soldiers compare in general? Was there any stereotype formed, like during the Napoleonic Wars?