Which one to buy depends on a whole lot of things - your preference, your local dealer, appearance opinion, etc. I don't see that there would be any quality difference between the two - all trucks break.
I had a Ram 2500 with the 6.4L Hemi, and I towed a 12,000 lb fifth wheel RV behind it all through the Canadian Rockies. It did great job power wise, I could almost always accelerate if I wanted to no matter the grade. It got 7-9 mpg with the 21,000# GCW load. Power wise, the Ram 6.4L has proven it will run circles around the GM 6.0L, as the GM is down 50hp and 50tq when compared to the 6.4L Hemi.