I love these coins--they have a great popularity, are pretty low mintages in proof, and are great UK designs. Just got my 2016 Britannia, and it is beautiful!!!
The only Britannia I have is in a Legacies of Freedom set (US Mint [2003]) but I do think they are most lovely. Mine's like a reverse proof though the indication is that it is uncirculated.
Mine is coming by slow boat from Great Britain. I wish I could find the 2014 Proof at a decent price. I have the 2013, 2015, but was caught napping when the 2014 came out. Beautiful series of coins.