Offer your thoughts or opinion on the input financial query or topic using your financial background.

Mortgage or not?
In addition to the other answers, I think you would also need to account for the increased utility and maintenance costs on the more expensive house. Typically it is recommended to budget 1% to 4% the cost of the home per year for routine maintenance. While it likely won't cost that much every year, you will have those expensive items come up (e.g. roof, HVAC) that come up periodically. The larger house will also cost more to heat/cool. Depending on where you live could also have increased property taxes.