Speaking only for myself, I have experienced no audio dropouts with the March firmware. I have experienced video dropouts on the Bourne Supremacy HD DVD, and I would characterize these as a nuisance. It happened once, with about 30 minutes left in the movie. I backed up, and it happened again. I backed up again, and it was fine. After that I could not replicate the dropout.
As far as audio is concerned, I have only had a "problem" with DTS HD MA. Occasionally when using the >> or << buttons on the remote or chapter selection from the disc menu, I will lose audio completely and my receiver will flash between DTS HD MA and whatever it was set to before it began decoding DTS HD MA. If I rewind a little and press play the sound returns. Again this does not happen frequently, and I would characterize it as a nuisance.