Yea mate, WordAI really is overpriced IMO too, which is why I didn’t rank it higher in the cost-effectiveness rankings. Now, it did change more than a few words, but I see how you would think it’s less than 80% unique. TBS is also great, but only in terms of functionality and the easy interface which allows manual spinning to be done quite fast. As for their thesaurus, I think they have a lot to improve.
WordAI is probably the most famous content spinning service. Many people swear by it and the quality of the content it produces and it is not empty talk. But let’s see how it will spin my short story. WordAI has two modes of spinning – “Standard” and “Turing”, with the latter being the one that produces better results. I will spin the text with both of them.

Imo it is not possible for google to detect properly spun content, it is not worth computing power it requires. They can do this using ngrams for example, but it is uses a lot of queries. And for example article spinner I coded beats this algo, so google cant detect that the content is spun. Manual spinning is also good but it takes more than 30 minutes per article.