I have the z71 liners so can’t speak to the others. The z71 liners are pretty good, no real complaints. Do what you would expect them to do. I did like the liners in my 2017 a little bit better.
I have a 22’ ccsb 4wd. I get between 13 & 14 city driving and 17 +/- on the highway. Towing our travel trailer I’m around 9.5, my bass boat about 12. All combined, I’m probably right around 14 average across the life of the truck.
Mine (22’ LT CCSB Z71, 6.6 gas) has a payload of 3562, but I don’t have a sunroof, 5th wheel prep, or extra battery. My GVWR is 10,650. For additional reference, my dad has a fully loaded 21’ LTZ Z71 w/ the Duramax. His payload is around 3350. He has the 5th wheel prep and everything.