Went from a regular cab to an "extended" cab because I drive with the seat all the way back leaving no room in the regular cab for any seatback adjustments to change position on long hauls.
One down-side I noticed which is probably exacerbated in a full crew cab - my view down into the bed while loading is more limited than it was with the regular cab.
I do value the extra storage and also it's convenience. For one example, on a photography trip around Yellowstone last year, I was making numerous stops at promising locations. I also found it a lot more convenient to just open the back truck doors to get cameras, big lenses, tripods, etc. Going around and climbing up into the camper 3 or 4 times at every location to get all the stuff out would have gotten very old after twenty stops or so.