After a multiple decade break, I consider myself relatively new to the hobby. My old-newbie view is that a lot of the perception about TPGs is marketing, despite the fact that it does in fact add liquidity and some assurance. Obviously each of the two big TPGs (PCGS and NGC), want to be viewed as superior to all other TPGs, and PCGS does a lot of work to be viewed as superior to NGC. In fact, a recent article I read about an auction in a leading coin magazine broke down how many lots were in PCGS holders versus how many were in NGC holders. Go figure. Obviously the slab cannot improve the coin but it does add value to any transaction involving the coin. Once the debate about marketing and market creation regarding TPGs is resolved, can we talk about CAC?
All sarcasm aside (If I'm breathing I'm looking for ways to be sarcastic ), it's entirely reasonable for an educated opinion to differ with that of the TPG by a point, especially for borderline coins. When considering the total volume of grading they do, even the egregious examples we see here are an infinitesimal percentage of the total. And in truth, if the TPG and I disagree on the circulated/not aspect of the coin, I regroup and look at it fresh, to see what they might have caught that I missed. There's value in that.