I tested the Bergger "contact printing" paper for them and found that it is not a contact printing paper at all. It is really an enlarging paper. It is NOT a silver chloride paper, which is what all gelatin silver contact printing papers are or were. Iodide is added to the Bergger paper. Iodide is found in films. Hence the Bergger paper is extremely fast. Although the Bergger paper can be a lovely paper I suggested that they not call it a contact prinitng paper since 1) it isn't and 2) the market for enlarging papers is far greater than the market for contact printing paper. All of the great prints by all of the great printers of the past who made contact prints, Weston, (Edward and Brett), Adams, Evans, are prints on silver chloride paper. Azo is the only paper made today that has the look of their great contact prints.
I have also used the POP paper distributed by the Chicago Albumen Works. If you have perfect negatives and like the reddish-brown color, their paper can be lovely. Personally, I like a neutral black and do not like the "old time" feel of the POP, but that is purely personal taste.
Too often prints on POP as well as prints on Platinum/Palladium are lifeless and dull. Those who make them think they are beautiful--just because they are on POP or Pt./Pd. But almost never does one see (do I see) a really rich POP or Pt/pd. print. Almost never. The Pt/Pd prints are usually weak with poor tonal separation and the POP prints are usually very flat. Perhaps it is the case the modern films just do not allow for the kind of negatives needed. Or maybe this is part of the reason: it is probably that those making these prints have developed their film in PMK. A developer that yields flatter, duller negatives I cannot imagine.