We had a ground drive and converted it to hydraulic. ground drive is ok as long as you are moving but sometimes it is nice to be able to adjust the speed of the beater depending on soil_stubble conditions as well as being able to creep up to stones and get a couple or more whacks at it rather than driving back and forth.I won't run another ground drive Just my opionion.
You mention trying a degelman, they are good machines. the hydraulic drive we bought was from Degelman and bolted right into place with no issues, I don't think kit was all that bad for price just in case you want to upgrade it at some point, good luck.