My neighbor has a DK35 which has worked well for him. I've heard others are having some decent success with the DK series. From what I've heard (and seen), the CK series have some issues and I wouldn't propose or suggest that model.
I don't know your terrain or what you plan on clearing, but that's a lot of land for a 40HP tractor. I hope you have a lot of time... Many will get a dozer in there for a couple days to knock off the harder tasks then use the tractor to clean-up and do the smaller/lighter tasks. If you "clearing" is similar to what I would need to do, I wouldn't put my tractor through that amount of abuse.
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