For me, it's more about the topic of a book rather than the author. For instance, I won't be buying Ptolus because the subject matter just doesn't grab me.
However, the author does play a significant role my decision to buy or not. Actually, so does the company name. Guys like Mike Meals and Bruce Cordell, and companies like Malhavoc, Paizo and Green Ronin have built up reputations for quality, such that I'll at least look at anything they put out.