Samsung’s S5 have nothing mucn new than its old smart phones. Though it have fantastic display, good camera, waterproof casing, good battery life and improved design. Though I really like its screen size which is absolutely perfect. There are alot of features in camera but most of them are useless and seems similar.
The things that might frustrate you is its finger print scanner, heart rate monitor is not completey accurate. Battery life is good initially but after 5 - 6 months it is completely frustating. There is not much difference between its old smart phone s4 and it isnt worth upgrading. I really had a bad experience with samsung. most of its devices starts hanging a lot after around 5-6 months of purchase.
I would recommend you to buy xiaomi mi4 which is much better than it and offers great features in much less price.