To paraphrase Thomas Jefferson: "The price of liberty, and a well-constructed house in Thailand, is eternal vigilance." Well, not exactly eternal vigilance, but vigilance lasting as long as it takes for the house to be built.
But the advantages to building your own house is that you get exactly what you want (hopefully) for a lot less than it would cost you to buy a similar house, and when the house is finished and if the location is right, it will be immediately worth up to twice as much as it cost to build.