I follow his publications a lot both on
OnCrawl and
on his site. I think he has some really interesting insights when it comes to semantic SEO and topical authority.
He also has some cool posts on how to leverage the power of Python to conduct certain tedious SEO tasks.
On the other hand, I do believe some of his case studies are a bit overrated because he mostly uses websites targeting low-competitive markets but, still I believe it´s worth checking them out.
In the end, for me at least, when it comes to technical SEO the guy is a freaking beast. He´s also great in other areas of SEO but I see him as an authority on topics around technical SEO.
My 2cc