I used Grammatica to review the writing of a student whose native language is not English. Unfortunately, the program did not perform well.

Over six pages of the student's work, the program missed many many errors, and it missed many problems of basic structure. It found no issues with the following passage:

"Since sixteenth century, not only by the Catholics, who kept old authority, but also by the Protestants, who encouraged new authority, persecuted and sometimes executed the Anabaptist. The shaping of the Lutheran or Swiss Protestant churches with the support of state and lords brought some followers the sense of the betrayal that compromised the spiritual reform with the secular power."

The one passage it flagged as an error -- an agreement fault -- was, in fact, correct.