I bought 8 of the wi07-12 units from here: http://www.electrodragon.com/product/esp8266-wifi-board-full-ios-smd/
I have assembled 2 of them with the ESP8266 SMD Adapter Board and headers and they have both gone very bad. I have an ESP-03 I got from Dx.com that works fine. I know how to use epstool.py and have flashed many times successfully and spent a bunch of time writing lua code.
These new ones just behaved very strangely. I was able to flash them and then it was like they shorted themselves out inside. The SMD board has an LDO on board for regulation, so the voltage should be right (and was by my meter) and I only connected up Vcc, Gnd, Tx and Rx. I checked all the connections on the adapter board and they all look correct. I'm suspecting they are either bad or there is something else that need to be done to get them to last, but I'll probably have to sacrifice another one to find out.
UPDATE (2015-04-11): Electrodragon support did not believe I had fried the board but they encouraged me to try again. Last night I built my 3rd one and was very careful to treat it well electrically. I did not flash the dev nodemcu, but rather, just the 20150213 release. I also used a different FTDI device and powered the board with the USB rather than an external source. So far I haven't messed it up. I'm hoping that being careful will pay off.
Working so far: