Reviewing about a Book

For me, criticizing a book is not about ego or a need to look smart, but more a matter of being disappointed if an author's lack of craftsmanship ruins my ability to get into the story and enjoy the book. I prefer authors who use English effectively (I think of George R. R. Martin and China Mieville, for example), but I can deal with workmanlike prose if it's basically correct and the ideas are strong (I think of Robin Cook as a prime example of this category). Unfortunately misused vocabulary or glaring grammatical errors can jolt me out of the story pretty quickly, and weak writing coupled with weak ideas can really piss me off. Another thing that can really ruin a book for me is if the characterizations or setting are completely implausible, not because the author intended it that way for effect but because he just did not think it through. Strong writing can make it possible to overlook this, but somehow it seems the authors I've read who really use English well usually do not make this type of mistake. But in any case, I do not call myself a fantasy or sci-fi "fan" and I am not likely to argue with fans unless provoked.