iamhistory, yeah, I guess I could say I have a few pointers
I've put on about 1,200 hrs on my B7800 in seven years. My first tractor and my battle tested friend. Never did I consider getting rid of it. I recently used it to set poles for a woodshed that I'm building; my Kioti was at the shop getting the rear axle cases resealed: not stressed because the B7800 was still available, AND, it was the perfect tool for the job (working in tight spaces). The B7800 was also useful in getting my Kioti out of a jam: I did something stupid and the Kioti pinned at the head end of building a road, full dump trailer in tow; trailer started slipping off the road and I had no way to go forward or backward with the Kioti; dumped the trailed load, pushed the material out of the way with the B7800 and then used the B7800 to pull the trailer back up on to the road (also had to use a cable and cable puller off of a tree).
Biggest thing is that of size. The B7800 is a small-frame tractor, it IS small. After operating this for as many hours as I have, and its nimbleness, I could almost do anything with it blindfolded I know it so well. When I started operating the NX5510 I was afraid I was going to be smashing into all sorts of things! (I put it to work in some tight spots.) Don't fight that sense, as it forces you to become familiar with the larger size of the tractor. GO SLOW at first! And later on ALWAYS make sure you're aware of the location/swing of your implements (having a box blade and a bush hog that are 1,000+ lbs means you can do a lot of damage if you hit stuff with them, stuff that you DON'T want to hit!).
Next is that it's "slower" than the B7800. That is, because it's drive-by-wire the response times are not like they are with the B7800. With the B7800 I can whip it around (stop<->go, forward<->backward) nearly causing whiplash! Loader is faster on the B7800 as well: Kubota biases for speed over weight, and, esp, with this smaller tractor if comes in very handy.
Going from an open-station tractor to a cabbed one takes a bit of getting used to. You have to be aware of what's around you when you need to open doors. If you're venturing into tight spaces always keep in mind where you can stop such that you'll be able to open a door (this means possibly anticipating getting stuck!). Also, with all the safety switches on the Kioti I am not hopping in/out of it like with the Kubota: I literally let off the travel pedal on the B7800 and jump off! (hard to do that on the Kiot, you know, with the door and all :laughing
I have a greater fear of breaking stuff on the Kioti than on the Kubota. From what I've read size is likely a big reason why: it's perhaps a little easier to make a smaller tractor beefier- the LA410 loader on the B7800, other than having one lift cylinder fail on me, is nearly indestructible. And breaking stuff on the Kioti is going to cost more to fix (and general maintenance is more costly too owing to the larger fluid capacities and the filters are just darn expensive [coming down in price though]).
The Kioti is VERY powerful. The ergonomics are nice. Perhaps the biggest thing for me was the stabilizers on the 3pt arms and the adjustable ends; and, the ability to raise and lower the arms from in the back of the tractor. I'd tried all sorts of things for the B7800 and just gave up: resorted to cursing whenever I had to hook up something that's not QH (I don't have a QH, but with the removable pins on QH equipment I can just raise the arms and then pin). I also got two additional rear remotes; I know that having a hydraulic top link on the B7800 would have made my life a LOT easier.
Oh yeah, the SSQA on the loader! Just about any newer tractor is going to have this, but having lived without one and now having one is a pretty big deal.
The difference in weight is readily noticed. One cannot appreciate how important weight is until one experiences a tractor that's got some real weight to it. My ground it pretty soft and I was worried about having too much weigh. It's just a fact of life for me, so I just make sure to not operate on soft ground (have to schedule projects/work based on time of the year). I shelled out for a higher-end box blade (1,200 lbs) and having that weight (and with ballasted rears) really means that this tractor can do some actual ground-engaging work.
OK, there's other stuff, but it's less substantial (but adds to the enjoyment of the Kioti- with a cab I have stereo [rear and front (when not broken!) cameras], avoid getting torn up by blackberries and bugs, stay drier and have heat and A/C etc.). The BIGGEST thing, however, is to understand what you need a tractor/tool to do for you. With the number of hours you've run your B7800 and having been on your property for some time you're in a good position to know. Had I attempted to get a bigger tractor from the start I may not have gotten it nearly as right: and I may have also tried doing stuff on my property that I've learned I ought not to. Doing "bigger stuff" means bigger equipment, which means "bigger price." As long as you're actually doing "bigger stuff" then it's unlikely that you're going to have regrets about your purchase. I have racked up 225 hours in the first year of owning the Kioti. It was engaged in a lot of activity, foremost, and one of the big justifications for the tractor, was in my fencing project: I bought a [used] dump trailer ($4k) just for this project! Once I had all the ground set the Kioti was used sparingly- I was too busy with the fencing work to have it doing other things, otherwise I'd have racked up more hours.
Implements will cost quite a bit more. I bought my grapple and pallet forks new because used grapples aren't readily available around here, and the cost of the pallet forks wasn't all that substantial (and here too these don't show up on the used market). Also bought my box blade new, though I came close to buying used (one I was interested got sold before I could establish shipping costs- yeah, paying lots of money for shipping was still placing the implement at a competitive price point). A 6' bush hog of medium duty (keep in mind that while "medium duty" might sound less than beastly, if one is truly "medium duty" it IS beastly- heavy duty and extreme duty ones are gawd awful beastly!) was also looking next to impossible to find on the used market around me (maybe one year pops up); but, like with many things, patience paid off and I landed one.
Not sure I'll ever get to the point where I can say that the Kioti is fully depreciated (like I can with the B7800), but I know that I'll now be able to do a lot more of the things that weren't possible with the B7800. I also view it as a kind of insurance policy, with the grapple I'm no longer trying to shove crap into a bucket- less abuse of my body = less physical down time (medial costs).
It's only been 1 year and 225 hrs. Would I do it again? I got my big fencing project done. Wouldn't have happened without the Kioti (and my dump trailer). I knew it would work for this project because I knew exactly what I was going to be doing: again, understand your requirements- I KNEW I had access to a lot of material just up the road from me; this would require POWER and a trailer- I had 85 run in total for one stretch of fencing (a few more for other places). I had some early issues with the cab leaking and a twisted loader (both promptly resolved). And then at 200 hrs (approx) I noticed a leak at the rear axle casing; it was also readily dealt with. I was fortunate in the none of these issues got in the way of me doing actual work: I was pretty much done with my fencing work when I noticed the axle leak).
In case you hadn't run across it, a thread on my tractor is
here.