My wife has applied for a visa to the US twice & both times she was successful. The first time was when we were not legally married & she came to States on a student visa. She got that in Bangkok. More recently, she received a tourist visa to the US-the 10 year maximum length-which she acquired at the US embassy in Vientiane, Laos.
The employees at the US embassy in Laos were fantastic. Actually, we got to know them a bit as we also made numerous trips there to register the birth of our son, get his US passport, social security # etc. The politeness, efficiency and fluency in English really set the US Laos embassy apart from any government office I've gone to in Thailand or the US!!!
A detailed account of this whole experience can be found by clicking here.
OOPS! I can't post a link yet...sorry will do soon.