Here are my two trucks. Both are 6 inch rough country lift kits with 35 inch Tires. My trucks were pavement princesses and the lifts were perfect for that. Both trucks had 3.73 gears so I only lost about 1-2 MPG. I also did not notice a huge difference in the ride quality. I have had trucks with 4 inch lift kits but I was never happy with that little of a lift. I think 6 inch is perfect. Both sets of wheels had 4.5 inch backspacing. I lift every truck I get.
Jarrod