If you consider that you can spin articles with Search Engine Optimization (SEO) in mind it definitely makes Spin Rewriter 9.0 worth the money. Your articles will now be able to rank in Google for your keywords you want to rank for. The more content you can produce and put on your website the quicker Google will rank you. This allows you to quickly create scalable evergreen content that will rank for years.
Only standard WordAI spinner showed 12% match for me in Copyscape which is very good I think. Also I will add that for SPAM links in general you don’t need any quality at all. if Google crawler can’t find connection with other spinned articles – goal achieved. Sorry, but I don’t see that with expensive spinners as Copyspace shows that in plain sight.
Any article rewriter or paraphrasing tool basically scans through the content you provide it in order to look for all the words that it can replace with suitable synonyms or substitutes. Every replaced word will appear bold and highlighted in a colorful text. Clicking on the word will give you details such as original word or other suggestions, you also have an option to add your own word. By clicking on the original word, you can go back to original.
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.