So Grandad4, you think the hydro is fine for some discing and rototilling? Also, you mentioned one being heavier....why is that, and does it matter? I did notice the TC40D being heavier than the TC40, and I assumed that a hydro would weigh less than a manual.
Like you said I'm not farming 200 acres and even if I do, I think the Kobuta will still be a very good trade in! I did love driving that Kubota and I would think enjoying driving your tractor should be kinda important also. I just loved where all the controls were located, it felt very natural and I didnt feel like I was looking and feeling around all over the place for all the different gear levers. Also I've read some threads about NH TC's (might of just been aTC30 problem) almost breaking in half at the clutch housing, and the TC40's having some electrical issues. I know driving a tractor for a couple months would make everything second nature, but I think I would feel like that with the Kubota after only a couple hours. Can't knock NH though, my uncle in TN has a TC65? Anyways, what he does on a yearly basis with it is amazing, especially clearing some ridge paths that seem hard enough just to walk let alone drive and work a tractor!
Jenkinsph, as usual, has it pretty well nailed... tillers are not hard to pull. I've been running a 72" tiller behind my hydro L4610 (about the same tractor platform as an L3830 with a bit more hp), for 8 or 9 years now with no problem. You do want enough tractor so the whole rig doesn't bounce around too much when you try to till the odd football-sized rock, but the hydro actually has an advantage in being able to go slow enough to allow the tiller to pulverize the ground. Many straight drive tractors in this size range don't have a low enough creeper range for a tiller to work like that, but the HST lets you go as slow as needed. As for discing, as long as it's sized right for the tractor, a few hours periodic use isn't going to cause any harm to a hydro. I wouldn't want to take on a 40 acre cornfield, but a few acres here or there are no big deal.
Regarding the comparative weights of the tractors, the L3830 and the TC40 are within a few hundred pounds of each other; not really enough to mean much in their capabilities. By the time you add in a 1,000+ lb loader, 900 lbs of tire
ballast and an 800 lb implement on the 3 pt, you're driving around a machine that tips the scales somewhere around 6,000 lbs; if one is 5,800 and the other is 6,200, or vice versa, it really won't make any significant difference in the work you can accomplish.
Here are some guidelines to consider... these are just my thoughts; maybe others will disagree: Most of the work you do with these small tractors is or should be in the 40 to 80 % of capacity range. If you're rarely using more than 40% of a unit's capacity, you could probably get by with a smaller tractor; if you're maxing everything out a lot of the time (pto hp, pulling power, lifting ability, etc.), you're overworking it and should invest in larger equipment. For heavy ag usage, I'd expect running at or near full capacity is more cost effective.
Although my equipment is Kubota, and it has been great, I wouldn't have anything negative to say about New Holland or several other major brands either. Certainly, the NH TN series have been rugged ag utility tractors for many years.