I've used one to tow a 5000 pound boat. With the Hemi, it did great.
My brother has had two. Sold the first one to his son who kept it to nearly 300,000 miles with no major repair needs. The second he still has and uses as a DD. It has somewhere in the neighborhood of 250,000 miles.
My advice would be to absolutley stay away from the V6, but I would also shy away from the 4.7. The 5.7 has significantly more performance, and gets about the same MPG.
I am surprised that you are finding them for less $$ than a Tahoe. When I bought my Suburban earlier this year I was trying to find a Durango/Aspen, but they were all priced higher than comparable Tahoe/Yukon/Suburbans.
2012 RAM 3500 Laramie Longhorn DRW CC 4x4 Max Tow, Cummins HO, 60 gallon RDS aux fuel tank, Reese 18k Elite hitch
2003 Dodge Ram 3500 QC SB 4x4 Cummins HO NV5600 with Smarty JR, Jacobs EB (sold)
2002 Gulf Stream Sea Hawk 29FRB with Honda EV6010