There are reviewers who are bound to love it regardless of what is in it. As such, it is hard to trust any review, especially one that only goes so far as to say it is "gripping" or whatever, but never explains why.
As for Bloom and his review - he assumes, like all academic critics, familiarity on the part of his readers with the text - why then would he need to tell people what it is about. His goal is to question the fad as justification for "good literature", which is a clever argument on his part.
As for his ego, his ego was big enough already, he was a massive player in criticism pretty much since he started his career.
This is not to say I am a fan of his, but then again my research and reading habits no longer belong on that continent - I am removed, if you will, from the Western Canon, and by extension the political ploys of theory-heavy critics and whatnot.
Still, he was responding to a specific point - what does 35million mean? does it mean that Potter is automatically good because it has sales? I would agree with him, it does not, and they are not necessarily "classics". The hype on them is already drying.
As for the BBC reviews, they bordered on polite to downright scathing. Nobody really taking the book very seriously. I'll let you all make your mind up over it, I am not going to read it unless someone does a lot of convincing to make me.