Blu82, A few thoughts:
1. Weight in a tractor is great if you're doing traditional field work with 2WD. Still, I've noticed that taking a tractor that's quite heavy to begin with and then adding an FEL can turn the machine into a real slug. Road gear is often only useful if there's no grade, or nothing in tow, or both. Even in the field, almost any grade will make the tractor labor and sometimes require a lower gear. The lighter Kubotas, like my
L4300 or N80's very similar
L4400 are quite agile machines whether there's a loader mounted or not. Starting from a dead stop in road gear is no hassle and doesn't require much clutch slippage. Contrast this with a heavy rig that might require you to get it moving in a lower gear and then try to shift on the fly....but then I'm talking the 'old school' tractors of my youth.
2. As someone unfamiliar with tractors, an expedition into the unknown with an off-brand is the last thing you need. As has been pointed out by others, the Big Three are big for a reason; a totally polished and professional approach to tractor design, manufacturing, marketing and support. They best meet the user's needs in one or more of these categories. Due to your unfamiliarity (no fault in that, we all had to start somewhere) any issue that arises could easily cascade into something serious before being addressed. That being the case, wouldn't you want to buy from a manufacturer whose products rarely have issues? If issues arose anyway, wouldn't you want a support network that could provide a remedy quickly and easily? A network that would encourage you to resolve seemingly minor problems and issues before they turn serious?
3. It would be good to choose a tractor that helps you keep your options open. Big tractors are great. However, at some point the work that justified a behemoth will be done and only the recurring small and medium jobs will remain....jobs the big boy isn't well suited to. Farm out the work that requires heavy equipment and you can get by with something smaller in addition to saving wear and tear on your nice new tractor. Compact size, tight turning ability, and ease of shuttling between forward and reverse are golden qualities when working around trees and structures. You could find ALL of these things in a 40-50HP CUT, but not in larger Ag machines. A good CUT in the HP range indicated could do the small and medium jobs that'll make of the bulk of your work and help clean up after the big jobs. That may be all you ever need. Later on, when you get more experience, you might consider one of those large used Ag tractors that are so readily available in your area as a second machine...if you still need bigger.
In your shoes, I'd be looking at Kubota
L4330 to
L5030 with HST or New Holland TC40 to TC55 with supersteer & HST. Don't know the JD models, so can't help there. With HST, you'll sacrifice some HP on its way to the ground, but the ease of operation and increased productivity should more than make up for any losses.
FWIW
Bob