I think it mainly depends on the context. Like, in my case, I use "~ㄹ까" informally when I have daily conversation with people. (for example, "우리 뭐 먹으러 갈까? (do you want to go to eat something with me?)) This form is also used in articles to raise questions. For "~는가", I think it's more used for formal reasons, especially in articles. I can't think of using this form in daily conversation :-) I hope my answer helps.