Although a short test, forcing you to select lists with many things you may not agree with as being "most applicable" overall, I was surprised by the accuracy of the result. My wife had found this and asked me and many of her friends to do it, and everyone felt their results were accurate. It is fun to read the descriptions for folks to see how they square up with what you know, (especially when they even agree the comments are applicable to them).
Comparing the characteristics of our different personality types highlighted communication issues which my wife and I had long since addressed. It was still interesting though, to see them quantified so concisely.
Read the summary of the "analytical thinker" and "dreamy idealist", comparing the wants, needs, expectations and methodology of both, and it appears to be a recipe for disaster. Awareness and proper communication, however, changed that into a well rounded and formidable team. We had run across the same thing years ago with the other test I referred to, identifying us as an INTJ and ISFJ.
For those wanting to improve communication and cooperation within relationships, these tests may be more than just fun. If you both agree on the results for each of you, comparing them can be beneficial in understanding the other person's reasoning and figuring out how to best coordinate your efforts as a couple. Other relationships can likewise benefit from this approach.