I have a Ford (which is now Case-New Holland) 24hp compact that is 35 years old now and a 47hp Kubota. Both are hydrostat. The way that I use my tractors, there is no way I would have a compact tractor without hydrostat. Just ask this question; will you mainly just load the tractor in a long straight line? Or will you be frequently changing directions and/or speeds? That would be the determining factor(s) in my opinion. Test run both systems as you expect to run it in service to decide which one best fits you and your usage.

And tier 4 would be a deal breaker for me, too. They want you to have an annual service that includes a computer flash. My Ford has been in the shop once in 35 years for replacement of a front wheel bearing that I should have changed myself. I still don't understand that one going bad, but........

Popular tractors like Kubota have a surprising amount of aftermarket support. A couple of years ago I stuck a limb through the radiator of the Kubota. The plastic grill didn't offer much resistance. Kubota wanted $900 for the radiator. Aftermarket was under $200.