I am not sure if it has been reported by anyone else (though I thought I had seen it somewhere) but I am intermittently getting audio dropouts, like it just mutes for a few seconds with my BD-UP5000.
I have a very basic setup:
A Panasonic plasma directly connected to the BD-UP5000 via HDMI. No receivers or anything.
I have only tested standard DVDs and a few BD, I think the issue is mainly happening with DVD though.
I have updated to the most recent firmware and the issue is still happening.
I am considering taking the thing back and getting the LG BH200 but I am not sure if that may have more problems.