From my experience around tractors, and around construction machinery, hydro transmissions are just as reliable and durable as gear/clutch transmissions. I have a farmer friend who I once asked about this. He said, out of most of his new equipment, he has to do more tinkering/adjusting/clutch replacement/etc. on his gear stuff. He said he rarely if ever has to mess with the hydro stuff. I think the key to hydro longevity is to keep the fluid clean, and filters changed just like the manual for your machine instructs you to. I will say this, once you own a hydro machine, it is very hard to go back to clutching, especially if you have a loader.