So far I love it. It made the ride firm, but in a really good way and I feel grounded. I no longer have the 5 hour bounce after going over a bump on the road (slightly exaggerating the amount of time), less roll on turns/curves, and there is much more control of the truck. As far as Lift, I was sitting at 38" from floor to the bottom of the plastic fender stock up front and 40.25 in the rear. I am now sitting at 38 7/8" in the front and 40.5" in the rear. I did not make any adjustments to the coil overs as I was told by ICON that they come set for their maximum recommended height (2" to 2.5"of lift on a stock 1500 Sierra non-AT4) from factory. I also measured from the floor up to the bottom of the plastic fender because I didn't change the tires. If I recall correctly, it is recommended to measure from the center of the hub up to an "x" point if you are making additional changes. This is my first suspension mod, so I could also be wrong lol.
I looked at the Fox kit, but most of the info I found online stated that Fox users would eventually switch over to ICON. I debated between the ICON and the Fabtech kit, but I wasn't able to get enough info/reviews on the Fabtech's. Granted there is limited info of the ICON & GMC combo, but I liked the adjustability. I found a really good deal online that saved me a few hundred bucks, so I placed the order. The Kings looked good, but I couldn't justify the additional costs for my intended use.