Having sold hundreds of iPhone 5s's when I was selling B2B, I have to say I was fairly unimpressed. Not great battery life over time, if an employee left with iCloud enabled it was a whole affair with Apple to get them to reset the device and allow it to be reused, and the brick style design is not very comfortable overall.

My favorite is the curved back, as is on most Motorola's and some LGs. Personally, I stick with cheap LG phones ($100 or so) that are rootable/rommable. If the phone gets damaged or I want a newer phone, no skin off my back, biggest concern is just moving Signal Private Messenger over to the new phone I get :P