If you are looking for a Hemi, go with a 10 or 11. They had valve casting issues up to (maybe into) the 09 model year. My 06 is on it's second engine - 135000 miles when it blew up.
The '09 and up have a better stereo also - with the touch screen and the AUX output and the GPS that doesn't require a physical disc that goes into the unit.
The Hemi is thirsty. My '06 gets between 12 and 12.5 on average driving around town. It only has a 17 gallon tank. I expect to fill it every 200 miles. For pure interstate driving I can expect 13.8-14.5 mpg. Towing, the 5.7, I believe, is the only one rated for 7,000 lbs. But with a load behind it, expect 8-9 mpg.
However, it is one of the most comfortable trucks I've ever had. Lots of visibility and head room (I'm 6'6"). It is actually shorter, narrower, and lighter than the current WKII models.
Besides the size of the fuel tank, the economy of the 5.7, and the casting of my engine, the only real complaint I have is that there are no drip rails so when you open the door in the rain, the door and your arm get soaked. I know, pretty weak argument.
I'm actually thinking about selling mine to get something more fuel efficient, but I need something that will tow my XJ, and there is something cool about a Jeep towing a Jeep to the trailhead.