Are you talking about handling around corners or responsiveness straight ahead? I didn't notice a big difference when I went from the stock tires to my current Toyo's, but I did it at 5K too so I really didn't have a lot of time with the stocker's. My E rated tires are definitely a harsher ride...
I parked next to a dodge ram yesterday with 275/60/20 Cooper Zeon LTZ's. It was a great visual how a tire can look so different as my 275/70/18 Toyo Open Country which is the same diameter tire as the Cooper, looked like "the small doughnut in the box" next to it.
From another expert:), these are awesome but expensive in the 18's. I haven't had serious snow experience in them but they worked well in the little bit I did have. I have 27,000 on them and they look like they will go another 27k. They are siped and grip great in the rain. They are quiet on road.