I often find myself comparing GreaseMoney with the Netbeans swing builder for thick clients. Its great because you can deliver a quick UI without worrying about the underlying functionality. But where GreaseMoney differentiates itself is in its ability to mock a live web page. By live I mean one that is already deployed on production. Never underestimate the impact of mocking a feature on a live website. Changing the innerHTML of a few HTML elements and hacking out some JS can get you quick results.