I have to agree with 'dutchman'. I think the idea of "product reviews" is totally misplaced where collectibles, vintage, antiques, etc. are concerned, mainly because the reviews were intended to compare more or less identical, branded, mass-produced commercial goods where it's simple and possible to meaningfully weigh apples against apples.
Even an expert's grading of something like a coin or collectible paper money may not be the same as another's. When it comes to that level of refinement, I don't think it's appropriate to have non-expert buyers giving "product reviews". Somehow too, the very idea of slapping up a "product review" by a layperson on a rare, possibly OOAK item rankles.
A collectible or vintage item is likely going to have aspects (not just wear and tear sort of issues) that will set it apart in some way, however subtle, from one that appears similar. I understand the OP's outrage at having someone who has purchased a "similar" item from another seller seeming to grade his own listed item -- and right up front on the OP's listing at that.
The inference is that if eBay is displaying a "product review" from another purchase, the product itself must be identical, i.e. the review must apply equally to the OP's item. However, the OP's item may actually have important differences from other, similar collectible items that has nothing to do with manufacturing quality or "good value for the money".
The buyer's comment? "Very fair price. Many on market for much more". He's talking about the other seller from whom he purchased a "similar" collectible item. There are no UPC codes to compare identical collectibles (a silly concept in itself). How can anybody determine whether this buyer knows what he's comparing? This is just rubbing salt in the wound from the OP's point of view.
No, eBay cooked up this brilliant idea without giving full thought to the implications for those of us who sell items you can't compare to stuff you can buy from Wal-Mart et al.
