need help buying mower

I've look all over the web & this is by far the most informative site I’ve found but after all the reading I still haven’t answered my own question. So I thought I would ask the pros. I am a homeowner with 3 &1/2 acres of flat level ground. I’m going to buy a ztr mower mostly for the time cutting. My question is should I buy a homeowner grade mower like Toro, Simplicity, etc. or spend 1500 –2000 more & get a commercial grade mower? I do not plan on mowing commercially but I will be mowing my Mothers yard (she has about the same acreage). I would rather spend the extra money now than have to work on it later. Would it be worth the extra or is homeowner grade good enough for what I have to mow? If it’s worth the extra what mower would you suggest?
Thanks for your help.

 

If you can afford it, go commercial. 7 acres per week is not necessarily you average homeowner usage. What else do you pan to do on properties? If money is not a great concern, consider a sub-compact tractor. You can do many projects.

 

Right now all I want to do is cut the grass in as little time as I can so I'll have more time with family & hobbies. The price looks good on the homeowner models but I'm worried about reliabilty & speed.
What brand would you suggest in either category there are so many to choose from? I've looked at kubota & ferris & was impressed with both. I liked the hydraulic deck on the kubota & the suspension on the ferris. One of the threads I read said if problems occur with hydraulic deck & drive shaft on the kubota it is much more expensive to fix. Are problems with the kubota common?