I have a similar 3 acre yard you described. I bought an Exmark pioneer s 60 inch at the beginning of summer. Have 18 hours on it now and I am totally happy with speed, power, ride comfort with suspension seating, cut quality, and durability. Was the right choice for me with dealer I trust.
If you are thinking zt there are a lot of great brands that have their own selling points. Others will offer opinions as to why theirs was the choice for them. For me it was Exmark. Some others include ferris, Scags, gravely, john Deere, and hustler. Research, find a dealer, have a budget in mind, and demo all you can. Riding and cutting with what is available locally really helped me decide. One will feel right and do the job you want.
Ask specify questions and this site will give you lots to help with your decision.