1.) Most of the really interesting ideas that he posits are conjecture. He provides scant mathematical proof for these and there is some skepticism in the mathematical community that some of his conjectures are actually true.
2.) He appears to take credit for a number of ideas that are not his. Some of the concepts he waxes eloquent on as though they were created by him pre-date him in publication by a decade or more and were definitely developed by others.
3.) It is an excellent treatise on complexity theory, but the hype exceeds the actual intrinsic value. It is a brilliant work but spotty, and falls well short of earth-shattering.
4.) Wolfram is an egomaniac with delusions of grandeur writ large. Make no mistake, he is a very bright fellow, but he attributes far more value to his original ideas than they actually warrant. But then, this personality flaw is well-known and documented.
My take is that you should read it and learn, but take some of it with a grain of salt. The basic mathematics is well done, but some of his conjecture is more sketchy. I'll add that going into what makes it sketchy requires a fair bit of mathematical background or you likely won't see it. Overall, it is an interesting book but no bible by any means.
Having met the guy, worked with people who worked for him, and knowing about the true story of where Mathematica came from, all I can say is truer words have never been written.
He should get credit for being a far greater self-salesman than pretty much any other mathematical physicist around. If that's the kind of credit you're seeking....