The salesman would no doubt love to end up selling you both
Buy the tractor, if you want a nice mower then get a finish mower to pull behind it (you can find them and small bush hogs at farm auctions alottttt)
The zero turn is a great mower but thats all they will do. I would opt out of a belly mower on my tractor and go for the pull behind (will save you money and headaches in the long run)
you can buy a really decent used riding mower around here for 5 or 6 hundred bucks....take care of it and it will last a long time.
I hate to imagine the price a "Good Quality" JD zero turn will run you (i'm sure you allready know)
On the farm i manage we have two toro zero turns. Great mowers but that is all they do and they mow alot more than 12 acres a day
For the fields we use two large 100+ hp tractors and 15 ft batwings and when tuned the fields look like they have been mowed with the zero turn
At home , My reality

i have a couple ol MTD Riding mowers , 1 for yard and one for the more ruff terrain and dream of an ol tractor one day