Now that silver has come down a bit I am looking into buying some ATB's, 5ozers.

My preference, because I love the Western U.S. would be the 2010 versions, not a real big fan of the Eastern historical parks. I see that I can buy about 2 entire 2011 sets for the price of one 2010. Not being a numismatic expert, I am asking why. Is it the parks themselves? The first year of issue? What makes the 2010's so much more?

Another side issue. I see these going on ebay for quite a bit more than from Apmex or Provident. What gives?