It's not a good movie.
There are no two without three, and after two films, a third was made to finish a trilogy that had already begun to derail in the second film. This film, in fact, was a desperate effort to recover from the bad step, but it ended up definitively burying any vain idea of a future fourth film. The film is weak, and if we compare it to its predecessors, it becomes even more tiring. The biggest problem is an erratic and poorly written script, but the weak and naked jokes also detract from the film, which never really captures our interest.
In this film, Mollie and James are taking care of two grown-up babies, but they face financial and marital difficulties from the moment she is fired and starts to stay at home, forcing James to accept the job offer of Samantha, a young and rich seductress who will try to break their marriage, leading to several jealousy fights and a climate of instability in the home. At the same time, they decide to adopt a street dog, who is the main protagonist of this film, and who will start talking to Samantha's poodle, in a funny rivalry relationship. As in any romantic comedy, it is predictable that everything will end well, between several twists and turns.
The cast continues to include John Travolta and Kirstie Alley, but both are shadows of what they were in the first film. There is virtually not a minute where they come close to the performance previously achieved. Both seem aware that this movie is a mistake and shouldn't have been made, or at least it shouldn't have been made the way it was made. The dogs' voice is provided by veterans Danny DeVito and Diane Keaton, and they try to do everything they can to defend their work, but the material they've been given is bad. Lysette Anthony just doesn't do more than be annoying.
Technically, it's as bland and uninteresting as the others: the cinematography doesn't bring anything new or particularly remarkable, and the sets and costumes are pretty much what we'd expect to find. The soundtrack is good enough, but it doesn't justify watching the movie at all.