I am sure that there are advantages to using one when mocking up you engine, trans, radiator locations. But at the price they sell them for I wouldn't use one. If you had a shop and turned out a number of cars over time, they might be a good investment. But if you are only doing one car every so many years, I wouldn't think so. Might be good if you could rent one for a short period (weeks,etc.). But what the hell do I know, hey may be everyday commodities for the average home shop.