Well, looks like the Angel Sensor folks have (finally) officially thrown in the towel. Not really a surprise, as they had gone silent for nearly a year after delivering their crowdfunded product over 2 years late. They did release code for their open-source SDK, and there is a community of developers who have forked it on GitHub to continue development.
Too bad they gave up, as the promise of a truly open source wearable with an array of useful sensors is lacking in the QS space. That being said, at least I received my units (many others never received anything). They are still new/unopened in their boxes if anyone wants to make an offer.