Some collectors will only acquire pristine material, especially investors, and any defect is reason to ignore that item. No matter the cost. Other collectors, usually in the beginning mode are more tolerant of defects and do not spend much time looking at pulled perfs, slight toning, or excessive inking. Like much of philately, there is a wide range of preferences that philately tolerates. One of the joys of the hobby in my opinion.
I would add that most PRC Liberation Area collectors are more tolerant of what would be called defects in other areas due to the extreme conditions these stamps were made and used. Other areas, like to above Mei Lan Fang sheet is usually discounted for any perceived defect, no matter how slight.
Looking at catalogue realizations will assist one with determining what to pay and what to avoid.
Usually a certificate will (Or should I say should?) list any and all defects, but a value statement is seldom given. Just remember that a defect may appear after a certificate is issued. Rough handling, storage conditions and many other factors may affect any paper product.
But it is your collection, and you should collect how and in whatever manner suits you.
But eBay is certainly a problem area for most collectors. I am happy that this dealer refunded your money.
You must be blessed with good luck right now considering your other post. I think I would go buy a lottery ticket, and I don't gamble.
Best wishes to you for continued happy occurrences.
According to the dealer, one of the many characteristics is that the white paper should be shining under LED light, but the one above doesn't. I recently bought a CTO one, and I notice the same characteristic. See my attached.
I used the same technique to spot a semi-fake/repaired scott #628 from a Taobao seller, 泓润收藏 .
1). The centerpiece seems legit after comparing with my CTO under 100x magnifier.
2). Then I put it under my LED light. The centerpiece's white paper is shinning, but the margin's is NOT!! I look closer at the perforations. The centerpiece is carefully glued to a new margin and re-gummed.
Who would have thought of that?! I didn't. It saved me alot of my hard-earned money!!