The Aviator certainly is cool rig. Too bad they didn't "fly"...
If you are getting a significant discount and an extented warranty, and you like it better than an Airstream or whatever else, why not? If you plan to trade it in a couple years, might not be a good investment, but if you like it and keep it for the long term, it may be a pretty good deal.
I would, however, go through the extended warranty with a fine tooth comb looking for exclusions. Water damage is a common exclusion - which can be a major cause of repairs if you have a leak on the roof or around a window that does damage to the walls.
2005 F-150 FX4
2013 Rockwood Roo 23 IKSS