Fuel millage and sluggish is the only complaint I have heard from people. Do a DPF Delete and those concerns go away. I only have 2500 miles on mine so there haven't been any issues.
Current Mods: Recon Smoked tail lights & 3rd Brake light
By the end of August: Recon Smoked Headlights & Roof Markers, 8K HID, 6" Fabtech Long Arm, Amp Research Steps, Fuel - Gauge 20" Wheels, Bakflip cover, H&S MaxxMini, MBRB Exhaust, 2 10" L7's 1500.1 Kicker amp.