Its funny because hydrostatics are about 90% of whats sold any more. Even of the gear drive transmissions, the straight stick between the legs ends up being more popular than a syncro because its cheap. There just is not much demand for a good gear drive transmission.
There are benifits to every transmission, hydro's are very easy to drive and have the least amount of wear parts - to the point that I'd say a modern hydro is more durable than a gear drive. The drawbacks are less power to the PTO as its not as efficient, and they are not great for applications like tillage where your under a heavy load continuously. However its wonderful for mowing and loader work, which is what most people do.
Gear/Syncc/GST and the like put more power to the PTO and are cheaper. However they require much more skill to drive and don't provide many speeds for mowing and constant RPM work. They are durable, but rely heavily on the clutch which will need replacing at some point in the machines life which is a very expensive job.
Bottom line -- drive each one, price it out, buy what you like. None of these factors should sway you away from buying something other than what you personaly want to operate.
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