I've read that there is up to a 3-4 hour difference. If battery life is critical to you, id go with the 1080p.
Also depending on your budget, the new skylake versions will be available soon i believe.
You need to decide what is most important to you and go from there. I personally want skylake but not sure it'll be worth the premium. Looks luke the new version will be a bit more expensive according to what I have read
Best of luck. I'm in my own predicament trying to decide what i want, especially with new products coming later this month