I haven't seen a lot of longer term review of the X320, and I know some forum members may be on the fence between X320 or other tractors (often higher end models). So I thought I may share my 5 year ownership experience with you all.
First of all, problem areas:
* As some of you have seen my JD seat issues, I went through 2 seats, and I could have easily gone through 8+ if I am insistent on warranty replacement. If you use the tractor below freezing, you will get cracks in the seat. The stock seat is junk and it is the worst aspect of the tractor. For less than $200 you can get a seat upgrade through eBay, the non-JD seat is far more comfortable (high back, better support). It makes the seat time so much more enjoyable.
* Throttle cable: Mine would not stay at a half throttle setting, it would back itself off to low speed. Dealer repaired it under warranty once, did not hold, and I end up replacing the entire throttle control assembly out-of-warranty, which was pricey.
* Starter solenoid: The problem started a few months ago, and got much worse in the last month. When I tried to start the tractor, I only get a click when I turned the key and the starter would not kick in. At first, I thought it was a bad battery, so I had my jump start kit, still nothing. I measure the voltage, it does not even drop below 12V when the key is in the start position. After reading this post http://www.mytractorforum.com/12-john-deere-forum/205356-x300-owner-starting-trouble.html
I went ahead and bought a new solenoid, took less than 20 min to replace it and corrected the problem.
A couple notes on the solenoid, there are two part number for it, the difference is the mounting bracket. Do not follow Deere's recommendation by looking up the machine serial number only, mine was over 150000, so I bought the new part, just to find out it uses the old part. Take it off and let the dealer match the exact part for you. Also, the thread above referred to $246 for that part number on a X5, that is not true. I got mine for less then $20 from my dealer, it is cheaper than any dealer on eBay or Amazon. Not to mention it is always good to have the dealer know me by name when I walk in.
Now, back to the ownership experience:
* The 48" deck is exceptional, I only have the stock blade, it gives a spectacular cut. I leveled the deck, and absolutely no issue with lines or uneven cut.
* The K58 hydro has been rock solid. I have a slight oil mark through the vent hole, but otherwise no issue at all. I use it to tow downed tree branches, pulling out weeds and a small tree (that was before I bought my CUT). The hydro does not whine much, the tire would lose traction far before the hydro's limit. I have not changed the fluid, just no time to take out and flip the hydro over to drain the oil. I do wish the unit is serviceable, had I known more about this, I would have gone to a X530 or X540 when I bought the machine.
* I have been using it in the last two winters. The machine is stored outside and get plenty cold, but never had issue starting it or running it.
* I saw some overheating issue in the X5, I have never had heat related issues in any weather condition.
* I added the 12V outlet to it, very handy for adding a Battery Tender with the cigarette lighter connector.
* The MowPro battery is still running strong, the only problem I had was it failed to crank the engine once in near 0F temperature. And that was because I don't run it long enough in the winter to fully recharge the battery.
* Talking about winter, if you intend to use it for snow removal, you should get weights and chain. I have a couple hills on my driveway, snow is no problem, but if it gets icy, you can get stuck with one wheel spinning.
* Before jumping into the virtues of traction assist, I have done some experiment with my CUT which offers a flexible traction management. When I get into icy situation where I lose traction, locking the rear axle provides only some small relief (and that is with over 700 lb ballast hanging off the three point hitch). It may or may not get you going. But once I engage 4WD, it always gets the machine going even on glare ice where no car can go up. I have never needed to lock the rear axle in 4WD, so if ultimate traction is a concern, I would go to a X7 with AWD before bothering with traction assist in the X5. But I am sure you already know this, and Deere knows it too judging by the price difference.
* Engine power: I have never had issue with it running short on power. I really think most modern lawn tractors are over-powered, I have a 12HP Yamaha at my other house with a 38" deck, I can tell when the engine is under high load when I mow tall grass uphill, but rarely to the point of close to stalling the engine. With the X320, I have never noticed a change in engine pitch when it is WOT mowing.
* Steering effort: Honestly, if one is in decent shape, and you are not hanging a snow blower in front of the tractor, you don't need PS. Sometimes I have both the CUT and X320 out working on a project and jumping between machines, I have never felt the need for power steering on the X320.
* Belts: No belt issues up to this point. Frankly, I was not thrilled with a belt driven hydro, but it proves to be robust.
* Tires: There is barely any sign of wear after 300 hrs.
* Rust: No rust yet, but I am sure it could use a good cleaning and a couple coat of wax to give it some shine. But it is a tractor, and left outside all the time, so I have not bothered. The only concession I made is always put the Deere cover on it. The cover has held up extremely well.
So for those of you looking at a X320, I would recommend it, it will give you years of solid service. Outside of my recent solenoid issue, it is a machine that you can trust to work all the time, and you never have to worry "will my tractor start today, or will it mow" It is about as hassle free as you can get, it is nice if you don't have time, nor find pleasure in tinkering with tractors like myself.