I have. It's such a great series and yet nobody has ever heard of it. I always ask people if they have ever heard of it, already expecting people to say no. However, I did meet one kid who said he had. I was dumbfounded. We became great friends after that.
Anyway, I thought the first game had a cool, dark plot that was a refreshing change , and the judgement ring was exactly what I wanted to keep me from getting bored after doing multiple battles. However, it could have been smoothed out a little, and some of the characters were obviously just tossed in at the last minute (Keith).
Covenant was awesome, but I did have some gripes with it. Some of the characters weren't balanced that well (Joachim as Great Question = 700+ P-Atk), and the plot had too many jokes that took the seriousness out of the plot. Overall, though, the gameplay was much more enjoyable, since i didn't have to worry as much about SP, the crest system was awesome, the game was long, and each character had their own fun skill learning side quests. It's probably one of my favorite rpgs of all time.
I never got around to playing FTNW, but from what i heard, it wasn't serious at all, and the game was much shorter. Oh, and Yuri's not in it
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. I probably would enjoy it, but not nearly as much as the other two.