I ordered 5 of these things (at 7.99, now it is lower, wish I waited) and received them at the back end of the upgraded date range I expected to get them in. The price of the shipping upgrade was very reasonable also. It looked like BangGood was going to miss the deadline but they got them to me in 9 days. WELL DONE! All the units powered up and performed as expected. They are clean, production run, and what I wanted.
The problem? BangGood's packaging. It's just plain awful! Wrapped in what looks like a garbage bag, and inside, the units were wrapped in a big piece of anti-static wrap. One unit actually fell out and was free-floating in the garbage-like bag. They were individually packaged, as expected, set in a cut piece of anti-static material, but, the device was pushed so far into the material that the pins actually came out the individual packaging and were exposed!
Customer service was not very good but they were prompt with personal replies. The issue I had with them is it took a few days to ship, so if you upgrade to the 6-9 day option, expect it in 9 days and forget about getting it early. Still, they did what they said they would do and that’s good enough for me.
I have seen these on eBay for much higher. Banggood has a lot of neat gear and at great prices. Maybe that is why their packaging is so bad. I would have liked my items in an anti-static envelope or a box at least.
I will buy from them again though. Thank you!

This is really nicely built board. Besides built in WiFI, great thing is that ESP8266 is really popular, so there are lot of tutorials and libraries for it. If you need more power or bluetooth connectivity you might consider getting ESP32 board: http://bit.ly/2x3Teik