This is very exciting. They seem get the core right. First impressions:

1. Use of a modern programming language that is designed to solve embedded / concurrent tasks and doesn't have a crazy (relative) footprint. Still curious what the actual footprint will be..

2. Well designed set of official libraries (dc motors, servos, ..). Something most other open source projects lack or only have badly designed code (looking at you, arduino)

3. REST api as default. This makes it easy to integrate and communicate with, though the speed of the comm protocol will remain an issue for serial comms.

4. Testing and mocking seem to be part of the default api.

5. Good range of officially supported platforms. Though unfortunately arduino due is still missing (I use these mostly, so I'm biased)

Very nice. Hope this succeeds.