It's terrible to get rigth informations, when I apply for it at the embassy in Rio, the said to me that was 1 year visa, but here my Thai school said that was that doesn't make any difference, and even in the imigration they told me the same thing!
I'm going ever 90 days to the imigration since I arrive here! I'm in Chiang Mai
I do have a ED visa multiple entry, and to be honest, just not make any sense.. But my experience with ED visa, is... U can get year, but ever 90 days u have to go to immigration, just to prove that u still learning thai. After 1 year, u have yo get out of the country, and apply again for more 1 year