Those who are looking for apple iPhone 6, and those who are in a dilemma, just go for apple iPhone 6 considering the good battery back up, good performance and a handy size 4.7" when compared to 5s 4".
Even those are willing to use for the 1st time apple product may go for iPhone 6, as this a reliable and the best handset and in the worst case if you sell this device, you will get a fair amount handy. Go for 64gb version if possible, to avoid running out of spaceand you the enjoy the huge storage space in 64gb version.