My Take
Although this is useful when there is no access to Youtube, it is limited in search capacity. There are only a few useful search results for each topic searched. The quality of results can vary greatly. This would be good to use if necessary but could be a wonderful resource if it were more comprehensive.
How I Use It
I have used TeacherTube to provide students with visual resources in the Social Studies classroom. It is most useful in situations where there is no access to youtube.