... they're a very exciting device and incredibly cheap, and the supplied SDK libs look very nice, even though they aren't quite fully open source.
The NodeMCU boards are very useful even if you're not interested in Lua, they add power, USB and breadboard friendly headers in a smallish package.
I've started messing around with different ways to program them for educational purposes: http://nick.zoic.org/etc/flobot-graphical-dataflow-language-...