All of the keyboards mentioned offer something that the goldtouch does not. The Freestyle Pro and Ergodox both have fully split keyboards. the Ergodox and Advantage have ortholinear layouts for their keys. The Advantage has a scooped keywell. These all contribute a lot to the ergonomics of the keyboard which is the point of purchasing them over a conventional keyboard. They all will also last a lifetime of use, which is rarely the case for membrane keyboards, where the rubber membrane acts as a single point of failure that can rarely be replaced. Then again, you can buy 5 of them for the price of the other.
Another point this post highly encourages is buying used. While this is often a good option inside the US in suburban/metropolitan areas, the used market is not as good in rural areas and availability of used computing hardware in Europe and other parts of the world is often sparse at best. Still, if it is an option in your area I agree that it should be seriously considered.