I have both of them, and honestly I don't like either one all that much. However, if you are going to buy one, I would reccommend Final Fantasy 3. I'm not a fan of the dungeons in CoM, and I found the gameplay sort of boring. I loved the graphics though

. FF3 lasted longer for me and I enjoyed the amount of jobs available, but there really wasn't much of a story, which I strongly disliked. I'm actually not sure why I enjoyed FF3 more. Anyway, hope that helped a little bit.