have owned two 318 JD's. Decent little mowers. The Onan (now cummins) engines had a tendency to break rods. "Most" of the time it didn't do enough damage to anything, dinged up the block a little but usually could just pull them apart, put a rod and sometimes a piston in, and send it. The Comparable Kohler H-twins never had that issue to my knowledge. If you've seen the Onan's rods, you'd understand.
Had a 400 for a while too. Was a trade-in where I worked, I got it cheap and fixed it up & used it a while. Sold it to the neighbor who just HAD to have it (and put me in a bind for a mower because the craftsman died too). The 400 became a 200. What they never made a 200? Yes. Broke a rod off and neighbor is STILL using it to this day, vibrating and running on one cylinder. That was, 2011 I think? Pretty sure it was '11. I talked to him the other day and asked him if he was ever gonna fix it. As long as it's running, I'm not messing with it. Well ok then. So he owns a half of a 400 JD.
Bought a 425 once with a broken cam. Should have kept that one. Great little tractor. I just wanted a 455, and had to sell the 425 to get the 455 I wanted. Guy sold the 455 while I was on my way to pick it up. My luck. Then came to the realization that I really didn't need a mower that large for my little place so I picked up a free LX188 from a guy I used to work with (when they sold JD). He bought it new, to cut 6 acres of grass and realized quickly that it was not big or fast enough, so they parked it and it sat. I got it, had to rebuild the carb and put a hood on it, but it was like a brand new LX188. I loved it. But at the time I didn't think about it, but 4.9mph max speed, was slow. Replaced it with a G1900-S which I would still own if the deck wasn't rusty. Then got a $75 ZG127S, and put a $700 shortblock on it. Had 21 hours on the meter I think, she dusted the engine and abandoned it when warranty wouldn't pick up the tab. I think I have 140 on it now; no plans on ditching it anytime soon.
but yes the market for the larger mowers and garden tractors has kind of gone away. At the time a 455 JD and a JD 2305 (I think that's what it was) were within a few hundred dollars price of each other; so why would anyone get a mower when a full-fledged tractor was $400 more money, and would accept a loader, box blade, rear blade, belly mower, etc. We sold a ton of those little SCUT's before we got out of selling Deere stuff. Then the BX's got real popular, and I understand they still are. BX1500 was dirt cheap for what you get, BX1800 a better deal and better optioned. I doubt Kubota could sell a garden tractor (per say) for enough of a discount vs the BX, to justify it's cost to most consumers. A few maybe, but a few ain't paying the bills unfortunately.
someone mentioned a GR2120. Also junk. Maybe better than an old craftsman, but in time they also need repairs and such. I hated them for the customers' sake. At the time $12,000 and frequently in the shop, often transmission issues but also drive shaft issues, glide steer cable issues, glide steer issues. Rarely engine problems as the little engine is as close to bulletproof as they can possibly be-aside from running out of oil, infrequent air filter maintenance and overheating.