I was really happy with Máximo Nivel, for a lot of reasons including 1) The teachers are friendly and experienced, 2) all the employees are friendly and helpful, 2) the cost is low, 3) the building is very pleasant, 4) they have computers and wifi for the students, 5) they provide free salsa lessons one night a week, 6) they have a little commissary right there, 7) there is also a trusted travel agency on the premises, and 8) they provide a kind of home-base for their students, offering 24-hour support and advice.
On top of all that, they offer a bunch of great programs:
1) They teach Spanish to foreigners
2) They teach English to locals,
3) They train teachers of English as a second language,
4) And they coordinate, organize and support people who come to Guatemala to volunteer.
I was really impressed with them when they gave me a list of the managers' phone numbers and told me to call any time of the day or night if I needed help. It was great to know that I could rely on that kind of support in a foreign country. (Fortunately, I never needed to call anyone in the middle of the night.)
I mostly gave Maximo Nivel the highest possible ratings in gooverseas.com, but for Housing I lowered it a little to 8. The other students I talked to seemed very happy with the homestays that Maximo Nivel arranged for them, but the school was not able to help me find an apartment for my stay. They told me that is something they intend to improve upon in the future.
I also gave a rating of 6 for safety. Maximo Nivel itself is VERY safe. Guatemala, and Antigua particularly, is very beautiful, and I am so glad I went there. I'll definitely return some day. But visitors should know that there are dangers there, and even though Antigua is one of the safest places in Guatemala, one still has to be alert.