I've had a few top-notch developer friends request recently that a startup allow them to work as 1099 contractors for a month first. They see their time as by far their most valuable asset and they want to learn more about a startup before committing.
In reality, with work-for-hire employee contracts, anyone can leave and anyone can fire for whatever reason. And that's what Paul English does. Contract-to-hire just takes all the expectations and paperwork and emotions out of it.