I have the Mcgaughy's 8" 4 link kit pushed to 10", running Fox reservoir shocks, it's a good kit, but could be better. As far as all of the hard parts, they are top notch, I would have rather that they used a multi-rate/progressive rate coil spring, but as is it still rides a bit better in the front than stock, probably would be even better if I had just left it at 8" also, but that's my fault. I can't comment on the rear lift for their 6" kit, but should be just a larger block. I honestly chose this lift because I liked the way it looked and it would do the job for what I use my truck for. I could have spent more and went better or even cheaper and bought something like a rough country, but for the money I'm still happy with my purchase and it'll give me something to tinker with as I get it dialed in to exactly where I want it.
Honestly if I were only going around 6" and buying purely based on ride quality and not looking at aesthetics, I would probably have went with the Icon lift.