Snips is a Voice Assistant with privacy in mind. You can let Snips process all queries on a Raspberry Pi 3.
The Snips Assistant needs at least a Raspberry Pi 3 to run. But Snips introduced the concept of base and satellite. The Base handles all the hard work, and a satellite can be a cheap lightweight device which will listen to a wake word and delegates the hard work to the base.
Poor language understanding
Very few skills available
Integration with Home Assistant