Get a 15+, preferably 16+ for the better touchscreen.
11-14's have rust issues, the rear windows tend to explode when you turn on the defroster, 4wd engagement motors tend to go bad and half-engage the front hubs giving you a horrible grinding noise, seat heaters and random electronics like to go bad early, the turbos were pretty laggy those years, 2011's specifically had intercooler issues with water vapor causing misfires, and the slip yoke on the drive shaft wasn't lubed from the factory so it'll eventually start sticking and cause a jolt when you gas it from a stop (the Raptors' were nickel-plated, making them slicker). Other than random shit like that they are fun trucks to drive but the newer models in 2015 were so much better.