I purchased an '08 GMC 3500, see Sig, 18 months ago, had 112000 miles on him. Its been a great truck, yes I goes into regen if you do a lot of short trips, but I use mine mainly for towing. I'm avg 9.7 - 10.2 mpg while pulling my 14600 lb fiver.
One thing to check for is a leaky transmission cooler line. The OEM used plastic fittings and they tended to leak at the cooler as mine was doing when I test drove it. GM does have a TSB on this issue and the dealer replaced mine at no cost.
Great truck, love the power, comfort, brake confroller and the fact I don't even know my trailer is back there while towing.
