I enjoyed Common Ground well enough that it was hard to leave the game to do the other things I needed to do for the day.
However, it has several odd flaws, most notably a few instances of technically poor writing. While I place story, characters, and gameplay very highly in my list of qualities to judge a work of IF by, language errors are terribly distracting for me. If this does not trouble you, I would recommend Common Ground very highly.
If you share in my distraction caused by little errors, I recommend it anyway, especially if you want to play a short, easy game with an interestingly and unusually told story as well as well-developed characters.