You are asking people here to justify the purchase of another bike? What's not to justify?

Seriously though, if you plan to tour, and the bike fits, I don't think you can go wrong with the LHT. And you can also used it to commute, or run errands, or do the sort of riding you normally do on the mixte. Is it ready to ride now, or would you need to spend money on extras? And can you budget somewhere else to get that $200 price difference back relatively quickly?