Tom,
I recently went through the NH/JD search and asked at this forum for some suggestions... ended up with a Kubota M9000, so watch out! I love the machine. The M9000 has a higher capacity hydraulic system, and an intercooler for the turbo compared to the M8200. This should reduce engine stress and hence improve engine life. No problems other than a punctured tire so far. The loader cycles very quickly, even at lower rpms, so much so that I rarely use the cylinder wide open. The joystick is well designed and easily allows control of the cycle speed. In 4WD the tractor will easily knock over a 4 inch tree (probably bigger, but I haven't tried yet), and the loader/bucket is rigid and strong enough to drag as big a pile of sapplings as you can get behind the bucket. The tractor with the loader, and cast iron rear wheels and antifreeze in the tires feels stable. Although I am novice, so I don't have a great comparison. Before I had the loader added, the tractor, and the rotary cutter alone seemed a little rear heavy when on the road. Now with the loader, no bucket, and the cutter in place on the 3pt hitch, I feel more secure on the road. Like you, my goal was square bales on 50-90 acres. I was warned by my neighbor that if you need to move hay quickly, or get tired of storing and trying to sell one square bale at a time, round bales are easier, so little extra power to pull a round baler would be nice. Here is where the M8200 will out do the JD/NH machines in price and capability. The M9000 with Cab (90 gross/ 80 pto HP), and a very heavy duty front end loader with quick-release bucket, 7 ft. Hardee Willimams rotary cutter came in at less money than a JD 5410 with a Cab but no loader or cutter. I spoke to brand associated and non-associated users and mechanics. No one had negative experiences with Kubota, most all had similar good luck with the Deere. One mechanic did mention that he saw more engine problems with NH than Deere- no experience with Kubota for that fellow. Truck mechanics told me that all the really big engines use the wet sleeve technology that JD uses not the dry sleeve engine used by the Fiat/NH. The Kubota parent bore technology is apparently the same as the old Ford tractors which some say "take a licking but keep on ticking!" For me, dealer support was a big issue, and the Kubota dealer in Lexington, NC, Sink Farm Equipment was tops.
I can't stress enough how much easier the job is when you breathe air-conditioned, or heated, filtered air in a tinted, quiet cab. Charcoal filters are available for spraying as well. If the budget allows for a cab you'll only give up the fresh air on a cool spring or fall day- so take a break and breathe, then get back to work. (Oh, you'll also give up skin cancer, emphysema, and hearing loss.)
Good luck,
Steve.