I read the funniest article why Rey is NOT a Mary Sue.
Talk about apologetics.
OF COURSE she is a Mary Sue. One of the most obvious and annoying EVER!
Let's examine the evidence: She has never left her planet but somehow flies the Millennium Falcon as well as Han Solo and even shows him a few tricks. She's never seen or heard of the jedi mind trick but she successfully uses it anyway. She gets in a battle of force will power over a lightsaber with a guy who was trained for years and she beats him, with the weapon flying to her. Then she uses it to defeat him in a duel. Finally she flies off with Chewbacca but since she's such an awesome pilot he lets her have Han's chair because he knows that his decades of piloting experience don't measure up to her experience of a couple of minutes. She's better than everyone, she knows it, and she acts accordingly but everyone loves her anyway because she's just that awesome even when she's being snarky or bossy.
What's the issue, seems logical to me. If I were the main character it's how I would do it all. Oh wait, that's the definition of Mary Sue, isn't it. Well shoot.