Difference between single rear wheel and dually rear wheel

I towed with a SRW F350 for years and I was very pleased with the stability and performance- until I bought my first DRW.

My experience has been that the DRW just makes for a lot less driving fatigue. I could immediately tell the truck was more stable. On long trips I can set the cruise and really just relax and enjoy the driving- which I did not do with the SRW.

I guess If I had a DRW and a SRW it would depend on how loaded I was and how far I was driving.