Shade said:For me, the reasons are as follows:
1.) FC1 did a better job remaining faithful to the canon of every edition of the game. It melded things from OD&D, 1E, and 2E with greater success than FC2. To me, that's a big boon. To those who dislike the canon fiends, I can see why they'd prefer FC2.
2.) FC1 went into greater detail on the layers it presented. Despite the fact that the layers of the Abyss are infinite, and the Hells limited to nine, the FC1 layers felt more developed.
3.) The obyriths. FC1 ran with the idea of the pre-tanar'ri demons and really expanded the game by developing the obyriths. FC2 chose to simply ignore the ancient Baatorians.
4.) FC2 made some poor design decisions when updating some of the fiends (or choosing not to, in the case of the kocrachon). The nerfing of the amnizu's spell-like abilities, for example.
5.) FC1 did a better job compiling all the non-primary-focused unique demons than FC2 did with the dukes of Hell, for example.
FC2 is a great book. I'd peg it 2nd best for the year. It just doesn't live up to FC1, IMHO.
I also agree with everything Shade said