My experience with modern coins and PCGS vs. NGC is PCGS is much more conservative (i.e., harder) to get an MS-70/PF-70. They also across the board value the coins they grade at a higher price. A sidenote is - I think there's a service that actually monitors the big-four TPG
's monthly (ANACS, ICG, NGC, PCGS) as to amount of sight-unseen trading, wholesale pricing, etc. PCGS usually gets a premium over NGC (and ANACS and ICG). That in turn keeps the most popular monthly TPG
in the mind of dealers when it comes time to buy/sell/trade coins. Real life experience = I have an almost complete NGC PF-70 (as well as some MS-70) Amer Eagles and the price differential with PCGS (which I have a number in MS-69/PF-69) and NGC is LARGE. Additionally, I also have a healthy 1932-1998 Wash Quarter collection with a number of both NGC and PCGS slabbed coins (and some ANACS sprinkled in here and there). PCGS is often times WAY higher valued and if I have an NGC MS-67, it's going to come back as a PCGS MS-66/MS-65 (for example). They're both expensive so I guess that's an equalizer <grin>!