The top 5 systems were deemed "partially useful" and received a grade of C-:
At the bottom of the list were the following "useless systems for education":
The University of Applied Sciences in Berlin makes the following recommendation: "The focus should be on teaching students about plagiarism and how to avoid it instead of investing time in using software."
The test overview and summary can be found in English here:
Debora also writes a blog dedicated to plagiarism: