I would agree that a utility tractor is more suited to his needs. And with 100 acres, he might want to go bigger than a JD5000 series if possible. I disagree with your view on cost. I guess it's true if you only shop green.
If you go beyond green, a CUT might be more suited to his budget and get them into a decent and respectably capable tractor right now. There are many large frame CUTS that are much less expensive than utility tractors. When shopping for my current tractor, I wanted a JD 5055E with a power reverser but didn't want to put out the $33K. I ended up with a Kioti DS4510HS (large frame CUT) and saved $14K. If I were to buy the same tractor used instead of new, it would be getting into the OP's price range. I looked at lots of other utility tractors, used and new. I had to get into some high hour stuff to get below 20K with loader (especially with the power reverser tranny I was looking for). So the lighter CUT can make a lot of financial sense. In general, Loader specs and hp are not much different between many large frame CUTS and many utility tractors. Weight / structure is the biggest difference.
That being said, I'd recommend the biggest well maintained used tractor the OP can get a good deal on that has the other features the OP thinks he needs (transmission type, 4wd etc).