Had they used a beefier transmission, they would be a great mower. They cut wonderful. They drive good. A little slow but my goodness it's a rider-they're most all slow in comparison to ZT's. Diesel engine sips fuel. I like everything about them except the fact that they don't turn tight enough and the transmission.
Honestly it should not sour anyones' taste for Kubota products. It was purely a screwup in engineering, it was not tested long enough, and most don't maintain them very well-and use them fairly hard. I mean, after all, it IS 4wd and it is a diesel isn't it? It should be tough-and it is, well most of it is. Every manufacturer has a sour note. Deere? F620 and F680 Z-track. Junk. Old Gator 6x4. Again, junk. They had quite a bit of stuff that was subpar, and they still do. There was also a V-twin diesel riding mower that did not sell well, also garbage. Lightweight V-twin diesel that vibrated your filling out at low speeds, a little noisy, wasn't stellar on fuel, and the rest of the mower wasn't just great either. Just a few examples. The GR2100 and 2110 were the redheaded stepchildren of the GR series, the 2120 has many updates to the transmission and glide-steer system. Longevity? I cant' speak for those, only been out a few years and most folks that buy them don't put a lot of hours on them.
What I wish they'd have done is kept the old G1800/G1900 around, and added electric power steering to it. They'd have had a top seller. That was the only complaint, especially the 2 wheel steer versions. The 4 wheel steer versions were easier to drive than the 2 wheels steer, they were fast, smooth, cut good, and built like tanks but no power steering.
But from a marketing standpoint not many folks want to spend $10K or more on a mower that won't cut any faster or better than a zero turn does, which a lot of times costs less and is a lot easier to work on, cuts better, drives better, more fun to operate, etc. Typically the folks that buy conventional riders are older and/or femaie buyers that are not willing to learn (or try to learn) how to operate a ZT. That's where JD owns the market. They still make a bunch of cheap throwaway riders that appeal to that market and they sell the pee out of them, lowes, homer depot, etc--mass markets. Make them cheap and sell a bunch of them. Kubota doesn't really do that, but I can see it coming sooner or later. I worked for Deere (a dealer) in the late 1980's and up until 2004, and I saw what Deere did to the smaller dealers, and am seeing the same things happening with Kubota so I don't think it'll be long. I'm surprised that the Z231 isn't seen at big box stores honestly.