Other article spinners also require that you enter your own custom synonyms manually or individually approve lists of potential synonyms as they are presented to you. This is another way of expecting you to do most of thinking, as opposed to expecting the software to be smart enough to instantly make judgment calls for you. Thus, one of Spinbot's main goals is to make the article spinning process as quick and painless as possible.
And then there is the amount of time that it takes to create content with this software. I have had past experience with text spinners and although it might seem like a fast way to write content, it often isn’t! By the time you have chosen a piece of content (or multiple pieces of content to blend together), put it in the software and produced content with this software, you could instead have created content that Google loves.