I've had the KO's on my Gen 1 Raptor, basically the same as the O2s' but with no tread cuts for longevity. I've also used the Mickey Thompson MT's, as well as the Toyo Open County MT's. I'm currently running the Goodyear Wrangler Duratrac on my new Raptor.
I really like them all, but I'll get into quick detail for ya. The KO's handle phenomenal on the gravel, and off road, they have great response and are very smooth.
When I decided to get the more aggressive tires I was expecting a lot less mileage but ended up getting over 40K per set which for what I do is really good. The Mickeys are awesome for traction but I noticed instantly the amount of rubber that was not contacting the gravel compared to my KO's and they seemed to be a lot looser handling on the gravel and off road at marginal speeds. Another thing to note on the more aggressive MT's the tread seems to be more Horizontal and when climbing or driving on side hills that are slick with snow, mud or ice, I notices the truck liked to slide sideways.
I am really enjoying the Wranglers with the aggressive vertical track for climbing and side hills, I instantly noticed the handling difference and how they will not allow my vehicle to slide sideways very easily on steeper slopes, even with quite a bit of snow. We got a foot a week ago and the Wranglers are hammering. They are also comparable to the KO's regarding the handling "feel" off road and on the gravel.