I've towed probably 50K miles with our 04 silverado and the factory brake pads are really good pads. and they last, at 130K miles the pads are just over 1/2 worn front and back. My recent experience on vehicles built in the last 10-15 years is that the factory pads have outperformed any aftermarkets I've tried in every case but one. The one being european cars that create huge amounts of black dust. In that case akebono ceramic pads eliminate the dust and provide comparable stopping performance. Not any better but equal performance.
MY opinion on the 2500HD is keep your pads till they need replacement, then go with OEM.