My experience has been similar. By viewer, I meant the CQ-editor. I've also had issues getting it to run. IMO, it tries to do too much.
Since Jupyter-CadQuery [0] uses Juypter as an "editor", it's much more mature and stable. And if the viewer blows up, the notebook still works and can simply be reloaded. Debugging via replay is great.
It's also nice that you can install Jupyter-CadQuery on a different machine, either via Conda or Docker. And the standalone viewer looks awesome. It's a really exciting ecosystem.
[0] https://github.com/bernhard-42/jupyter-cadquery/