I was unsure about the body style also, but preferred the look of the Chevy over the GMC. The GMC equivalent Yukon XL was actually less impressive on the interior, mainly due to the fact that they would prefer you to upgrade to the Denali XL, which is way overpriced. Other than the significantly overpriced Escalade ESV, there are no other large family SUVs with decent towing and cargo space on the market. I do not like the Expedition XL or the Navigator XL.
We went through Truecar.com to establish our baseline vehicle and options and it was amazing at how quickly the dealers around me were competing with each other for our business, most of the offers were just above invoice. However, in the end, I used the fact that all of these dealers were competing for my business and I negotiated with my local dealer and we beat the Truecar.com price by just over $1,000, which ended up being about $300 below invoice, took a total of 15 mins to negotiate the price. One of the easiest purchases I have made in a long time. Expensive, but easy.