Clockwork has been mostly very good for me too. There are some sharp corners that I've run into periodically (e.g. it can't observe tickers, they're just an always-present Waiter) that I've been trying to figure out how to resolve in a new library, but overall I've been happier with clockwork than with any other I've seen so far.

Quartz looks quite interesting though. Gonna have to explore it in detail, because I agree with most of their claims in the article. I'm not 100% sold on their solutions being actual solutions and not just "often an improvement", but that'll probably be clear after using it for a bit / reading it in detail.