I've read a few online snippets of Dr Bernstein's books, but haven't read them in whole, so won't express a view till I've done so, but my general impression is that he's not the sort of guy who you'd want tagging along on Friday night out.
"Come on, Richard, up for another pint here, mate?" "No, Scott, as I've explained in my book, you should eat no more than 6g of carbs at breakfast etc. etc." Yeah, well, it's been fun, see ya.
His often quoted law of small numbers seems like utter cowardice to me. Here's what he says:
http://www.diabetes-book.com/laws-small-numbers/
He approaches this as if it were entirely an engineering problem, focusing on uncertainties in measurement. That's correct, there are deep uncertainties in T1, but just bailing out and saying, "limit carbs and it will solve everything" seems to ignore that with cgm, we can make adjustments on the fly, in the moment.
All I know is that if I'd followed his advice, I would have spent my life saying, "ooh, sorry, I'm T1, I can't do that, Dr Bernstein says I can't.".
I take my T1 seriously. I'm rarely over 8 or 9. There's the occasional visit to the low or mid teens when I make a mistake. We're not lab rats, but Bernstein seems to want to make us so. I've visited about 20 countries. I think my experience of them would have been impaired if I'd followed Bernstein's dictates.
The irony here is that we all complain about non-T1s telling us, "you can't eat that", yet some seem happy enough with Bernstein saying the same thing.