I checked out several free synthesizers recently on an Ubuntu system. None worked on first try. Thought I got half of them working after a while (the others would have needed JACK).

On my Debian system youtube videos stop playing sound once in a while (video continues), thought I suppose it's not pulseaudio's fault (so just a general sound problem).

You asked ;-) (I still agree with you that it got better than it once was)