Re: New retina MacBook vs Samsung Galaxy tab s 10.5
Well, one is a tablet and one is a notebook, so they have different uses really.
Apple cite the 13" Retina Macbook as having 12 hours of iTunes video playback and Samsung cite the Galaxy Tab 10.5 as having 13.4 hours video playback.
Don't forget this is like comparing a Ferrari to a Kia. Of course the Kia will have a better fuel economy but it doesn't have the performance of the Ferrari.
If battery life is the only thing that is important to you then the Lenovo Yoga Tab 3 comes in at 15+ hours of video playback. Obviously, it's slower, heavier and, well, more rubbish... but there you go.