So to get this working you need to have an image of your disk ready at all times, to be able to go back when you need it. I suppose you have your Users (home) folder on a different partition so you can just whipe the root partition.

I'm glad with my Macbook. It's expensive, but it works. I've thought about moving to Ubuntu, which I use at work since five years, but still lacks in some points compared to the Mac. And finding a modern laptop that just works with Ubuntu, while being significantly cheaper than the Macbook is not easy.