I think that there's an amount of interest in Chase UR on Flyertalk that is a bit overblown due to the plugs for the card from various bloggers associated (or formerly associated) with Flyertalk.
While I'm not opposed to the idea of Chase getting its own forum, at this point Chase UR is still pretty new and who knows if it will last (think Citi with its Thank You Points).
AMEX and its MR has been around for a long time and not really expected to go anywhere.