It just means “back at you”

@chicaaalicee you could say “so are you” or if you want to be more unique you could say “look who’s talking” (i personally use that one sometimes lol)

If you’re Australian then yes definitely, other regions maybe not. ‘Says you!’ In response to a compliment or insult is effectively reversing the insult/compliment, and is similar to saying “that’s rich coming from you” but without the inherent negativity.

However, “says you!” is interpreted in different regions to mean “so says you” or “you say that (but I don’t)”. So be careful where you use this because the meaning appears to be highly regional.

“This observation of me is charged with ambiguity instead of outright dis/approval, but I’m going to do the expedient thing here and assume good will / pretend it doesn’t bother me.”

It depends on the context. Someone would say "I'll take that as a compliment" if what has been said may not be a compliment. For example, if someone says you're very loud, this could be meant as an insult or a compliment. Even if the person was saying it as an insult, you could say "I'll take that as a compliment". The other two aren't really used often. Someone might say "That's an honor" if they are given a compliment, especially by someone they look up to, but I wouldn't say it's common. In response to compliments, people tend to just say "Thank you"