Links not terrible if you take it for what it is. Plot wise its kinda stupid, but its like Legend of the Twilight in that its not really meant to be taken completely seriously. Its kinda like franchise wide comic-relief. Its obviously still canon in some sense since in Quantum they are playing R : X, and we see the Akashic Records tower, but I think if .Hack does continue on, it'll end up being one of those things where the it gets a more serious novelization or something, and that version will be the one labeled as official canon rather than the game.
Just my two cents.
If nothing else it has interesting characters.
I mean come on, Fluegel goes to such great lengths to look menacing and evil, and does such a bad job at it. Then spends most of his Manga screen time laying on a couch doing.. nothing.. XD