I agree, but then, there are reviewers who can give good reviews, while they haven't even
As for SPEW, being accepted into it is almost like an award, in a way. They only accept the best, so personally, I don't see why there needs to be anything decided outside of that particular organization for Best Reviewer, because I'll venture to guess that 9 times out of 10, it would be one of them.
That sounds like a good idea, though. :)
That's why I suggested that, while the Reviewer/Bannermaker/Beta categories should remain, the particular governing organizations of those groups should decide who wins it, considering they're more privy to intimate knowledge of the nominees' quality of work, etc.