This necklace is nice enough, but it really is just a replica of the one in the game. The chain is long (versus short on Roxas) and the pendant is low on details (which you can see in the picture)--mine even has a bit of a dent on it (but a very, very small one). The chain seems pretty sturdy (I just got my necklace in the mail, though, so I'll see what happens). The pendant is smaller than it looks in the picture--so, yes, smaller than the one in the game--, but it doesn't look too bad. The whole thing came in this coolio square box from Japan (everything's in japanese except for the english "Made in China" statement), so I was nerding about that when I saw it.
Overall, this necklace is pretty awesome and I really do like it, but I wouldn't recommend it for cosplaying.