My I suggest you look at few things before you make the spend, Please remember you will enjoy the cutting and want to spend more time on it. Plus look at what attachments will work with what you have.
Now I know the budget is 10K, but you do not need to spend it all! Lets look at what will last you a long time with the least amount of issues. Understand Warranties, power train, and Drive train.
Longer warranties mean the product will out last the average consumers lifetime. Longer warranty means the company wants you to be "not thinking about it" 400 Hr. over 4 years is good~ now 1000hr over 3yr. not as good for you, but 500hr over 5 years is all ways better since your cutting will be around 100 hr a year?
Remembering that all the companies use the same product in they're driving systems, look for the best but do not over pay for something that you will never use. The hydro's you get help you a lot when it comes to life of the unit, the minimum I went with is the zt3100 which is the low end commercial ~ so my thought is 6hr a day for 8-10 years of regular use in commercial setting will give me 25-35 yr. of personal use plus still giving me a good resale after 10-15 years if I want. I paid $5800 so after 10 years of use I can still get between 2500-3500 on resale costing me 2800 or about $280 a year about $10-15 a week not bad if you look at this.
Now zero-turn are not snow blowers or lawn aerator, so what I did was due to the bumpy lawn I rented a motorized lawn roller and after a good rain that lasted a few days You would be amazed at how awesome my lawn is now.
I run a 48" which I believe give a better cut then a 60", more passes but more handling around objects plus allows you different cut pattern since my next door guy, has groves in the lawn due to the same pattern he cuts.
I have a Hustler Fastrack SD, with Honda 20.5hp and a 48" cut and ZT3100, I hope I helped and good luck.