I have used Neuronwriter for a while now, and it is mighty and versatile.

It looks through existing content for your keywords, as many do, but it lets you choose which content to add in the base for creating your optimized article, which is really a plus.

The writing is AI, so it could use a humanizer filter, but who says it will not happen in the near future? And anyway, you can still review the text manually for a total optimization.

If you should buy only one AI writer, that would be the one.