Their prices are much higher than their quality level. Their prices are based on the local market, not on actual building costs. They are built fast and cheap and they put the burden on the homeowner to find issues and get them resolved before the clock runs out.
Make sure you check the flood maps, many are not in flood zone X. Also, make sure you factor in the association fees, they are often hundreds of dollars a month.
As far as mineral rights, few properties in the area convey those rights with the property, that isn't just a Horton thing.