After only few hours of installing, rebooting, and configuring, on the 3rd build attempt it started and succeeded in seconds!
I love the sound and the added subtle "light" selection for the GUI.
Thanks a lot for the feedback! There will be an official beta soon.
The new audio core required some very invasive changes in the way Stella's scheduling loop works, most notable the introduction of threading to decouple emulation timing from the interaction with the OS video system (which may block when a frame is rendered). As a side effect, timing has greatly improved; emulation should now run at almost the same speed as the real console for all games. I was able to run Pick'n'Pile (a particularly nasty test case that generates an irregular video signal) in parallel in Stella and on my VCS, and both played happily along in tune for a minute or so