If you're going to get a zero-turn, the Cub's are nicer (to me).
In the price range you're looking at, the JD's feel "different" than the decent ones landscapers use. I got to test a diesel zero-turn JD that was smooth as butter, while their standard JD's matched up to the Toro's we use. The JD's in the price range you're talking about feel somewhat chintzier and something else seemed to be missing. The Cub's felt pretty similar to the one I use daily (which is an $8000 Toro), just smaller.
If you're going with a garden tractor type of mower, the JD's tend to be more reliable from the guys I've talked to, and tend to be packed with more "useful" features for the homeowner.
See if you can find a "Power Center" type of dealer around you. They'll generally carry a few different brands, and should also offer some sort of service department. For an idea of a difference in price for replacement parts, find out how much a new set of blades are, how much the LONGEST belt is to replace, and if there's a few spindles (big round pulley wheels the belts wrap around) that need greasing, how much does one cost to replace.
Also, don't skimp. If you end up needing replacement parts, go with OEM parts. Your mower is one area where you're SERIOUSLY going to get what you pay for. I can save $10/blade, but the difference in wear rates makes it a losing proposition, and complete loss due to damage of a blade happens more frequently with non-OEM parts. Match OEM prices to OEM prices.
Lastly, Toro's aren't worth the money (to me) for the homeowner. They're generally pricier, but parts are WAY easier to come by. If you're a homeowner, the odds you'll need replacement parts should be rare enough that it shouldn't be a selling feature. I know you didn't ask about 'em, but figured I'd throw it in there. Honda makes some of the best push mowers on the market, but be prepared when you go to buy one. The price differential is huge, but again, there's a reason they cost what they do. They're WORTH it.