Jack wouldn't work as a main audio system. ALSA is used regardless of which audio router (jack/pulse) is used. ALSA by itself is pretty good until you open the wrong program and suddenly it locks the sound device. So if you want more than one program that uses sound to be running, there will be problems (perhaps music while playing a game). With Jack I've had similar problems as when using ALSA alone. Best luck I've had in audio production is to route ALSA to Pulse and Pulse to JACK, which is annoying to say the least. With JACK, my best bet is to use it only for audio capture and let pulse handle the output. Pulse audio is the best of a bad situation and probably the best bet for the Pyra. If I remember correctly, Android uses pulse and I don't remember sound issues for the few years I used that OS. As far as old pulse goes, yea pulse sucked when it first started gaining traction. It's pretty solid now unless you start messing with it. Disclaimer: I don't like pulseaudio, but I still think it's the best default.