Don't expect deep truth or drama, this movie is probably the best German sitcom you'll ever encounter and the closest a German script comes to the early Woody Allen.
The basic idea (don't show ur mobile to your partner) is not too clever and according to another review has been screened before, but the actors play well, not all of the story's twists are predictable and I enjoyed the movie.
Most of the jokes are about sex but you have to lack any sense of humor if you find them offensive or against heteros or homos.
Take it for what it is, a light comedy.