I vote for the MBRP. I've heard clips of both, and I think it sounds better than the Gibson. MBRP also has 2 different systems to choose from, theres the system that retains the stock muffler placement, and another one that relocates the muffler under the driverside floor. And I think you can get either system in aluminized or stainless.
SOLD-08 Unlimited X, "jeep green", auto, limited slip, hushpower muffler, Aerotech Interceptor gauge,Powerstroke tranny cooler, skidrow evap skid, AFE Pro 7 filter, Teraflex leveling kit, EVO control arm skids, 15x8 Black Rock 909's, 33" KM2's