I am currently using the esp8266, programming it in the native api.
Made it into an irc-bot so you can control it via irc instead of bloated http.
It is pretty stable, but can hang up if you produce serial debug data faster than the
buffer can handle, so just keep the debugging out on the uart to levels so it won't overflow,
the buffer, at which point the device will reboot
.
There are also issues with the ssl, it works if your device act as a https server,
then you just supply it with its private,public key etc.
But if you use it for https or use it for encrypted connections to any other protocol as
a client, you are most likely out of luck, as it doesn't support newer certificates that most
endpoints use these days.
There is a good amount of ram on the beast, that part is a joy to work with and much
easier when you arent limited to 750 bytes as i am used to on lower end pic's.
The best bang for the buck that i have found so far. Most of the major "houses" are making
full tcp stack wifi chips, but the price is at the $30 price range pr unit and thats before
you have added the glue components and pcb.