Prior to buying this, I was actually pretty set on the '07 Yukon, however there were certain features on the Armada that won me over. 1. Interior space - this vehicle has more room in the driver's cockpit the the GMC. Also, 2nd row has a lot of legroom. 2. 3rd row seats - I can't understand why GM has not gone to a fold flat 3rd row - I just leave the seats down until needed. 3. Ride quality is great - independent rear suspension does make a nice difference. Also has excellent ground clearance. I am one of those people that actually needs and uses the 4 wheel drive on an SUV. While the LE comes with street tires, it does have excellent manners off road. Traction control works great.
Power - engine has a lot of torque. Backup camera - this came included on the vehicle I bought, and prior to using it, thought it a gimmicky feature - WRONG! It's is great for backing in to parking spaces or other tight areas. Fold flat 3rd row seat. Ability to have either XM or Sirius.
As some others have said, more plush seats - while they are not uncomfortable at all, they are firm - could use better leather. Option for 20" wheels. Get rid of the giant chrome grille/bumper - allow for matching color. Fuel management system like GMC - goes from 8 to 4 cylinders to save gas.