I prefer Skype since although it has always been a huge CPU hog, its UI is perfect for beginners (i.e. family) and in the decade I've used it, I've never once been cross-sold some pointless feature the parent company are currently trying to promote.

Note Hangouts itself once was Gtalk, which I was a user of, prior to the first cattle herding on to Google+. Now Gundotra is out the door, there is no telling into which silo existing G+ users will be cattle-herded next. Hangouts might be technically superior (although I personally think Skype's rate-adaptive video is second to none), but the treatment of users by its parent company, and their endless thirst for personal data keeps me far away.

Skype just works, just like it has for the past decade, and just like I expect it will continue to in the coming years. I'd place a small wager on Hangouts being long dead, or at the very least rebranded before then