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.
As you can see, WordAI is a lot more loose with the meaning of the text and uses synonyms wherever it can in order to produce the most unique content possible – this one is calculated at 98% uniqueness. Again, the purpose of such content should be for the lower tiers where you would need a higher quantity of links with not that high quality content.
I've ranked websites in the past with spun content, and now they are still on #1 position of google. First year (2014) google found me because my spun was really bad, many paragraphs were just copied and my position drop from #2 to around #20 after a panda update. Later I cleaned all my text with better spun (I didn't buy any article!), my ranking went up again, and with more backlinks I reached #1 and it is still there

This time, WordAI calculates the spin it generated at 97% uniqueness which is basically completely unique. If you look at the text above, again, the first sentence of the quoted content is a bit confusing, but the rest is still good. I would even say that the last sentence came out better than the previous spin, but generally, yes, the above spin looks more like a human wrote it.

From personal experience Spin Rewriter is the best! like I still use it today. Its so easy to use (Just copy paste and the program do everything) Because of this tool I managed to schedule content and articles for 3 years, do you know how much time and money I’ve saved?!?! A LOT!!! Also i high recommend you pick their mothly plan if you are still in doubt