Don't worry about the Heater/AC. It just takes a little while to catch up but not a huge issue.
I love mine. Period.
'06 is the best year in my opinion as you get the 5. 9 with the 100 pin ECM (same as a big truck), the fairly smart transmission and a HUGE cab.
Two grandkids in car seats fit in it very well... ... .....
Rides great, quiet (Doors seals, cab, etc. ) and at 106,000 miles is still as tight as the day I drove it home new with 70 miles on it.
Leaking FSA fixed under warranty, behind the turbo coolant hose leak fixed by me, ball joints and knuckle u-joints by me at 70,000 miles. Almost forgot, a new louder muffler at 95,000 miles.
I have added an Edge w/Attitude, a Jake Brake, a rear overhead DVD player and a bunch of stainless trim.
16-17 mpg at 75 mph. 20 mpg at 50 mph. Towing the fifth wheel 11-13 mpg depending on load and speed (try to run 63 mph on interstate if possible).
That is it, all the rest is unmolested virgin truck.
Do it, you won't regret it. Oo.
Mike.