Their advice is not necessarily bad, but not particularly original either. They just beat their drums with half a dozen of opinions they paraphrase over and over. They seem to have certain experience as engineers, but I wouldn't expect them to be particularly good ones.
On the other hand, I know a couple of outstandingly good engineers I have worked with, who also have some mindshare on private blogs and conferences, but nowhere near the thought leaders, and definitely not on LinkedIn
