So I tried looking this up with no luck, so I'm here. When looking at a coin, what does PCGS see the difference between plus and pq...ie a ms65+ vs a ms64 pq. Are they both just designation for superior quality? Eye appeal?
An assigned "plus" grade means the coin almost achieves the next higher technical (numeric) grade. Star means the coin has (in the opinion of NGC) superior eye appeal. Usually given for coins with appealing toning or exceptionally stellar luster/strike. The star means nothing about whether a coin is low, middle, or high on the scale of the assigned technical (numeric) grade. PCGS has no comparable eye appeal designation. "PQ" is an abbreviation for "premium quality" and it seems that every dealer and every collector thinks their coins are as such. The term is used willy-nilly, and is not used by any of the respected third party grading companies explicitly.