Independent of outfitter, my recommendation is Kansas. Unless Nebraska is substantially closer to you.
Having hunted the ML season multiple times in each state, and all things being equal, I'd go the opposite route.
Granted none of my hunts were with an outfitter but I'd hunted some pretty good ground in each state.
While trophy potential might be better in KS, so is the wonderful potential for temps in the high 80's-90's, skeeters and fall allergies (if applicable).........I hate all three of these things so perhaps I'm projecting
Much depends on the outfitter and their ground though. Bad can be found in both states.
stillhuntin-
Do you have any expectations on trophy quality and what state are you traveling from?