Yes I've heard it used like that before in American TV shows. You are correct, saying 'aces!' or 'ace', means 'that's great!' or 'that's fantastic!'. Whether it's something Americans would say in real life, I'm not sure. It's not something I would say myself.

"That's ace" would be the same as "That's great". "I bought you a present", "That's ace!" - meaning "it's good" "Shall we go for a meal?", "yes, that's ace" - meaning 'yes i agree, let's do that' Ace would work in both examples, though it has a slightly more exciited feel to it, as if it's even better than great. There may be other examples, "I aced my exams" maybe would mean 'i passed easily'. I dont know where it comes from. Maybe tennis or the ace in a deck of cards or something else maybe.