Another possible solution is to consolidate vendor reviews. Perhaps giving each Vendor their own sub forums where there could be a section for "Offerings" and "Customer Reviews"
@dionysos is one person doing the reviews. A Michelin star system will still reflect that one person's experience. And given that he's a well-known character will likely get preferential treatment which skews the results.
The solution might be something more of a "Trusted Vendor" badge that is earned by vendors over time and by customer satisfaction rate.
I don't think the requirement to become a Forum Vendor is a very high bar to meet. I could be wrong.