Get a denali or an escalade. The l86 is awesome engine, plenty of power. The 5.3 will feel sluggish compared to the 6.2. The 6.0 feels sluggish compared to it. It also has dod, and thus gets great economy cruising down the highway. The magnetic suspension feels awesome on the highway, very smooth, keeps the truck planted even at speed. Been back and forth to Florida a few times in it, really cruising, and it rides great.
The new ones (2016+ i believe) have apple car play and the android equivalent.
The Denali/Escalade has heat/ventilated seats in front, heat in middle, and the third row folds flat.
Both have HID.
The new 10 speed is supposed to be great, with less issues than the early 8 speeds that jam, hunt, and buffet.
Best value? Denali with a bunch of options. Escalades are nice but I'd stick with a Denali. I don't like the tall taillights, and I don't know how much I value the extras the Escalades come with/can get over a Denali. The lights are a little nicer, interiors a little nicer, and has thee trick cupholders. I think they rate them a tiny bit higher in power but it's just a tune.