6wheel drive
I just started running a grader whith 6 wheel drive ( 772 John Deere) and I tell you it makes a difference, in what you can push, it helps me go a few more places on the job site ( and a few I shouldnt). In tight cornes it helps pull you around with a good load on the blade. not saying that it is essantial, but it nice to use, and you can turn it off. the big disadvantage I have found is the fuel. I burn a lot more in a day with it on all the time. I doubt I could do a full solid 12 hours with it. I havent tried Cats system yet. I know Deere gives you 15 or 16 different settings to select from going from non aggressive to very aggressive (top setting the front wheels want to spin out from under you. #8 is supposed to be the same as the back wheels)
Last year I had a new 160h without 6wd, and I would still take it over the 772 Deere. I find it to be a little nicer to run. Cab comfort, easy of maintainance, fuel economy.
Thats my opinion,