After 1.5 seasons on my CC Ultima ZT2 6)" ZT here is my impressions so far, but not sure if I'd recommend it.
Runs very well owing to the Kawasaki FR730V engine. I have a Deere with similar FS730V and both are real high performing runners and easy starters. On the ZT, one down side is the deck's blades. Pretty thin if you ask me. I am looking for replacements after 1.5 (2021 and half of 2022 so far). They are cheaply made of thinner material. They don't hold edges very well and the lift wings are literally wearing thing in non sandy soils. It has the ZT2800 HyrdoGear transmissions with spin on filters which is nice for annual maintenance. Yes, I changed them and their oil after first season, and will continue to do so every season. I have slopes of 40 degrees or a little more and mow them mostly cross ways battling skidding if grass or soil is more than dry, or is too dry. This leads me to my biggest complaint. TIRES. These are standard turf tires and are prone to skidding, and once started skidding, they not stop skidding until reaching more level ground. The risk of roll over has not really presented itself even on some pretty serious slopes owning to its low CG, wide stance, and propensity for the turf tires to skid. You'd have to totally abuse this machine to get anywhere close to a roll over situation.
At 70, I'm still doing my 4 acres at least weekly with this machine. My first season of mowing put 100 hours on this new machine so maintenance is going to be critical for me. I paid just under $4,000 for it in April 2021 at the local HD store since the CC dealer in my area didn't have any stock...seemed odd to me but that is what it was when I needed a ZT.
I think I'd recommend a commercial or near commercial machine as these CCs are MTD products and are of slightly thinner materials than I'd like to see now having used it for over a year. I'd definitely opt for better tires less prone to loading up with dirt and skidding. Yes, when they are not clogged, the still skid. I'd go for the new ZT bar tires with the rounded off shoulders, and just be careful making turns and direction reversals.
"Better to have more capability than you need than to need more capability than you have" has never been a truer statement. Still happy with my CC but I'm running it at the far end of its capability.