I have the Titan which in alot of ways is very similar to the Armada. i did a considerable amount of research before buying the Titan. At that time, no major thoughts of towing a TT.
The Titan and Armada originally came out with Pathfinder brakes on them, they finally made a recall and corrected the issue. I have a 2004 and if you look at the service records the original owner went through 3 sets of rotors and pads in 21,000 miles and never towed a thing with it. When I bought the truck, I had no intentions of really owning a travel trailer.
Things changed though when my grandparents sold their Newmar MH. I have an 831RLSS which is a long trailer for the wheelbase. Personally, I have alot of experience towing and I'm comfortable with my setup. Would it tow better with a heavier truck, I'm sure it would but, I'm comfortable with my setup and upgrades that I have made to the Titan.
The best addition I have made was the PowerStop Brake kit for towing. It has heavy duty pads and rotors. It was a night and day difference. If you do go the route of the Armada and decide to tow if you are within the weight ratings, it's a top recommendation of mine no matter what.
The only thing you have to worry about as long as you are within the ratings is the wheelbase, but again for me I am comfortable with it. The truck can still get away from you while towing and has plenty of power. I've had no problems at all. I keep it at 60-62MPH and it moves right along. I have had it up in the Adirondacks even without any problems.
It's best to look at all the real numbers and of course don't listen to the sales person about towing!
Also, X2 on the MPG, I'm getting about 8.5-9mpg towing with the Titan.
2012 Keystone Sprinter
Still sticking around for the good people and advice.