The sidewalls are heavier so they will be stiffer and if you are in cold weather, tires will take a few miles to "soften up". E range really aren't necessary on an SUV unless you tow or want a heaver sidewall for rocky terrain.

I too am waiting for Costco to get these in. 31x10.5/15
These are C1 load rated.
Costco have the KO's in my size and I was going to get those but the salesman said If I had a roadhazard issue they may not be able to replace them since the KO2's are replacing the KO's so I'll wait.

I had E's on a 3/4ton ford F250 and they were fine for carrying a camper and towing. I wouldn't pay more for something I don't need.