The whole towing issue points me away from a light duty, lawn tractor. Some of these units do not have a strong enough transmission to do any serious work and usually, not for very long. I would avoid the potential disappointment.
One issue, for me, and perhaps for your neighbor, is riding comfort. An acre of lawn can indeed take an hour, what with fussing around. That's a long time to be on a seat that kills your back. If your neighbor can swing it, absolutely step up to an X series and avoid the pitfalls of anything less. Last time I checked the difference, while substantial, was not prohibitively so. $3000 towards a suspicious cheapy? Or, $4500 toward a known good machine? Re-sale? No comparison.
It's a decision your neighbor will have to make.