WELL WORTH THE $$$...YOU BET. Super reliability if you buy a model that is engineered for what your needs are. I could have bought a 2 grand JD, but for mowing 5 acres, it wouldn't last.
The great thing about green machines is you can ALWAYS get parts and service. I've got almost 800 hours on my 8 year old 4210. Aside from fluid and filter changes (air, oil, hydro filters) the only part I have had to replace is one fan belt and one cracked pin on the FEL linkage. It still has the OEM mower deck belt and that looks nearly new, and I mow at least 80 hours a year and some of it is 3 foot high weeds.
I paid about 20 grand for my machine when new, there is one like it for sale locally, private owner, and no mid-mount mower. He wants 16 grand for one like mine with the same FEL. A 60 inch 7-Iron deck would add $1500 to the used model price. You show me ANYTHING comparable that is 8 years old that has the same resale value !!
Good Deeres are expensive, but the investment is well worth it in the long run.