Most of the roads around me have never been that great, and unfortunately some of the ones that are part of almost every route I ride haven't been maintained in years and years, and in the AZ heat that means they're crumbling. On section that's about 3/4" mile long was bad several years ago, now it's absolutely horrible, tons of cracks, tons of large aggregate showing on the surface, some cracks are 2-3" wide, most are just crumbly sections that aren't like the Grand Canyon but still in for a bumpy ride. Here's my unscientific addition to this unscientific testing thread: on my old bike, running a 28" rear tire and a 25" front tire (both Conti GP4KII tires) I had to slow down while riding along much of that section of road, but with my 32" tires on my new bike I can ride through there at full speed. Yeah it's still jarring, but I can do it. On the old bike with the narrower tires the bumpiness and jarring were just too much.
My riding is a few shorter sections of new pavement, lots of average pavement (not super smooth, not all broken up and crack-ridden everywhere), and some sections of truly awful pavement. The experience is way better on the 32" tires than it ever was on the old bike with the narrower tires, and on that old bike just going to the 28" rear (fork was too narrow for 28" up front) was already a huge improvement. I just ordered a 35" Rene Herse Bon Jon Pass tire to put in on my rear wheel to replace the 32" Stampede Pass tire that's now finally close to worn out. I'll stay with 32" up front because the front is running at lower pressure already and is fine and a better match for the width of my rims, but the rear is getting another bump up in size and I can hardly wait to see what it's like.