iPhone 6+. Had a 5 and lots-o-problems with it. First Apple product I have ever had that happen. I bought a Galaxy S5. I HATE it! Lovely piece of tech, but the software is somewhere between Windows ME and Vista. Going back to iOS. Much more stable and predictable. I'm pissed because now I have to figure out how to cheat the system so that i don't have to practically 1,000 to get it, based on contract this and that.
'nuf said!
If you have Verizon, what I did to get an early upgrade was add another fake line that cost me $10/mo for 24 months. Then they can switch the new phone to your old line (so you keep the same number) and they basically said the new line was an iPad or something, which didn't actually exist. I think the new line has to be a tablet. It was a rare instance of Verizon providing good customer service to me. It ends up costing $240 over the 24 months, on top of your current bill, but it sure beats the amount of money it costs to buy out of contract. Regardless of your carrier, I'm sure they can work something out.