One minor annoyance I noticed: The measurement readout is left-aligned and they aren't using tabular figures (all digits are of the same width). So when the reading changes, the unit jumps in position. Also, when changing between 99 and 100 the position changes significantly. They've got the space available to right-align the measurement results. Wondering why this slipped since they seem to be very concerned about user interface.
Appendix:
I've taken a look at their open source acknowledgements, looks like they're using FreeRTOS. This explains the fast boot time.