I'm actually still hearing some crackling since I changed to Win32 waveOut. It is not nearly as bad as before, but the sound quality still isn't as good as it was with 1.0.5.
I've just upgraded from 1.0.5 to 1.1.0. I now hear a similar crackling as described by the OP when listening to MP3s. The files are not corrupt, because they played just fine using 1.0.5. I hear the crackling every at random times, and it does not occur at the same point during playback. This is on ...