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.
I am extraordinarily dissatisfied with WordAI. They are happy to take your money – we spent a good chunk of coin, but also sent in two support requests that were never answered. In the end, we told them that we had to like their AI and their humans before we’d continue trying their service, so this article, which is a great analysis of the products shows that there are other spin services our there and we will definitely be trying out the competition.
Quality readable content is key here. Google, for example, will recognize that people are leaving your site soon after arriving if they perceive that your site or blog is full of junk content. This is called "bounce rate." If your bounce rate is high, then people are quickly leaving your site. But for the sake of your business, to build your online reputation and brand, you want people to visit your site, stay for a while, and then keep revisiting over the long term.