When I do care, I can be pretty good at reading people. I usually know when they are faking, when they're uncomfortable or when they're trying to manipulate me but it takes me a tad longer to figure out why.
If we want to go by type, the NFJs I know can read me easily although that could be because they've known me since forever. I usually can sense when my fellow NTPs are closing off the walls so I try to curb down my curiosity and not invade them (because I hate it when people do that to me). The NTPs can read me pretty well too (I feel). Not sure about the other types. I think I can read my INFP friend fairly well but one can never be sure. We're slowly building our trust levels so I'm still accumulating data and she's probably doing the same thing as well.