With all do respect, it isn't a good bang for the buck if it can't go up a hill. At $8k, the hydro (and every other aspect of it) should work.
Considering there are a lot of riding mowers on the market in the $1,000.00 price range, an $8k machine should be top notch.
If everyone that owns one knows the weak point is the hydro, then the hydro is crap. If only a small percentage knew the hydro is the weak link, then the hydro is good enough for 99% of owners.
Driving a 4wd mower up a hill is pretty normal in my book. They sell bar tires for this thing! Jeeze, it should climb!