I contacted Soledad to take some Spanish lessons during my vacations in Buenos Aires. She answered right away and I had my first lesson with her the next day. During the first lesson, which took place in her apartment, she identified my weaknesses when speaking Spanish and proposed some topics to work on in the following lessons.
In the few classes that I had with her, I was able to improve my use of the "subjuntivo". Moreover, she taught me some words and phrases of the Lunfardo (which is definitely helpful when you are trying to understand the porteños) and we could resolve some doubts that I used to have ("Is this expression common in Argentina?", "How would an Argentinian say that?").
The lessons are very well structured and Soledad can explain very well. If you want to learn or improve your Spanish in a relaxed atmosphere with a very kind teacher, I would definitely recommend taking classes with Soledad.