I am in the same boat as you , and today i went to test drive a 2014 GMC 4x4 double cab 5.3l v8 . Vehicle was great , i plan on building my own up with the MAX tow package and the 3.73 rear axle. I checked the payload sticker on the truck when you open the door and the numbers were spot on. The Dodge Ram payload is TERRIBLE so its like your almost forced to get a 2500 on the Ram model.
I also test drove a 2013 Chevy 2500HD extended cab 4x4 standard box w/ 6.0 v8 motor in it... I was surprised how well it drove for such a HD vehicle , compared to a ford f250 i had driven . I was really turned off from the interior tho as a 2500 HD is more a " work " truck and doesnt come as nice as the 1/2 ton trucks inside. You DEF could tell you were driving a truck since it was empty and no load was on it , so the rear end just felt super light , bouncy, and the ride on small bumps sucked . Im sure loaded up tho it will feel way better , but how often will you drive with a load on the truck and can you stand the drive everyday ? Thats what i ask myself as i drive 50 miles a day for work on the highway .
I do see that the 2015 Chevy 2500 HDs will be coming out early next year in 2014 with the " UPDATED" interior just like the 2014 GMC/ CHEVY 1500 interiors , so if you have time to wait , i think this would be the ultimate 2500 truck to buy. Your getting a nice updated interior , probably a smoother ride , and will still have the 3k payload and 13k towing with the 4.10 rear axle. But then again all you might need is just a 1/2 ton .