If someone forced me to watch either "Transformers," "Pacific Rim," or "Robot Jox," I would probably go with "Robot Jox." That's not to say this is a good movie. It's the very definition of a B-movie, but it's a good B-movie, and at the end of the day I'd rather watch a good B-movie than a bad A-movie.
The plot is ridiculous to the point of it being unintentionally funny at times. However, this is more of a "so ridiculous it's good" rather than a "so bad it's good." The two semi-sequels "Robot Jox 2: Robot Wars" and "Robot Jox 2: Crash and Burn" are more of the "so bad it's good" variety. By the way, that wasn't a typo, both of the semi-sequels were #2, but neither had anything to do with Robot Jox besides the fact that they had giant robots in them.
At the end of the day, this was silly, funny, and comprehensible. Fans of B-movies should know that a comprehensible plot is not a given by any stretch of the imagination.
If you like 80's sci-fi, giant robots, and B-movies, then I highly recommend this movie to you. If not, stay away. Stay far away.