When i'm undecided i look at the sell value.
Phones now do pretty much more than we could ever want.
I use the Galaxy Note 2 and its like a min pc at my finger tips. No Battery issues runs all day with Bluetooth and Wifi Enabled. The Note 3 is out now but i'm not seeing anything that's going to make me go WOW and to change at the moment. Its a Big phone, but for me ease of use is great.
The S5 it has a heart beat monitor and can connect to the next gen watches "Galaxy Gear" at a price.
Think fixable and resellable with your choice.
I'm not an Iphone fan so I couldn't say to you anything about the 5s
Its about this time of year new models are released see what the anticipation is out there for new models and see if you can get that on your contract
It may also be an idea to just keep waiting and then change when something you want is available. What ever you go for i think you will have to ensure its (4G) which (EE) is but for others reading