My parents bought a prefabricated house and never regretted it. At that time, prefabricated houses were far superior to solid houses in terms of thermal insulation. However, solid houses have since caught up. There were and still are high-quality prefabricated houses, just as there are cheap and high-quality solid houses. The advantage of prefabricated houses, aside from the construction time, is mainly that they are mature models at a fixed price and there are many house types. You can simply choose the best one from all the house types. Seventeen years ago, I renovated and modernized a solid house, and in the end, the architect exceeded the budget by 130,000 DM. That would not have happened with a prefabricated house.