Today two answers were posted to my question and both of them are correct. So I accepted the one which had better presentation and was answered first. Though I did it, for future reference, what is the etiquette i.e. which one should be accepted in these cases? The one which is answered fist or what is good to see? Does it solely depend on the asker which one to accept?
That is entirely on your discretion. The whole point is for you to decide which answer you find as a better explanation, regardless of time posted.