I've got a 2011 V6 4x4 with the factory tow package. I just finished a trip bringing an older car I am getting restored up through NY & NJ and into PA, including some time in the Catskills Mountains. The JGC did great pulling my 1850lb trailer with the 2800lb car on it - so I was just under the 5k limit. MPGs definitely dropped, but I didn't see any appreciable increase in the transmission temp except when going up the hills or when reversing uphill on driveways. I agree that if you were really towing a lot the Hemi would be better, but it is a no-brainer for me since like others said the MPGs normally on the V6 are more than enough to keep me happy. I tried to keep the speed while towing at 70mph and really didn't have any problems maintaining 60+ even on the hills.
I was pulling a brand new dual axle flatbed trailer with full brakes, so with a brake controller installed I felt safe and it definitely made me feel safer, especially given the weight I was pulling. Wiring harness plugged right in to the port above the parking brake and it everything worked perfectly (tekonsha p3).
Only other piece of advice I'd offer, and will note that I don't have a ton of towing experience, is that I got a quietride hitch which definitely was worth the price. No banging around back there plus a bit more stable feeling.