Not a fan here. We have one in my wife's Traverse. The only time it has been open is when we first got the vehicle (used so we didn't order it). I don't think the shade has even been opened in the last 2 years as I don't like the sun in my face while driving. Plus we don't have that many sunny days.
I am a good use case for the gasser as well. I drive tops about 6k per year mostly short trips as everything is close by. I bought at the end of February and only have 1250 miles on it. My current camper is only 5k loaded out and we are in flat Michigan. 2500 has plenty of payload for me. Ran out in my half ton with bikes/ roll top cover, paddleboards, and corn hole in the bed.
Recently did both the Retrax and steps myself. Steps took 15 minutes to install. Retrax was about 20 min to install. Just needed my kid to help lift it onto the truck.
Having done or doing yourself? All the bolded are really easy to do yourself. Might need an extra hand to lift the Retrax into the bed but my 11 year old was able to help with that.
I am doing nothing to alter my driving habits. I spent a good chunk of coin on a vehicle that I knew doesn't get great mileage. I am ok with the pay to play. If I cared about gas mileage I would have bought a tesla.