Originally posted by the dave
Wait, can you explain that a bit? The Zero series has better story quality, but BN has a better story overall?
Sorry if I wasn't clear, this isn't exactly what I meant. My point is that the Zero series had better story writers. The events they present, from the end of the X series up to Zero 4, is solid and pretty much never contradicts itself. There's a build-up from Zero 1 to Zero 3, along with Zero 4's conclusion, which slowly reveals more and more of the picture until you get a (mostly) complete package. Despite having the games released over a few years, it all felt like it was written as a single block, with the possible exception of Zero 4. That's why I say those games had the best story.
On the other hand, the Battle Network universe is my favorite from a personal perspective. They originally build a somewhat coherent world filled with interesting characters, which parallels our current Internet-filled world quite a bit. Some scenes were thought-provoking, or even touching, which is to be expected from RPGs. In my opinion, the series ending was especially well-handled. However, the overall quality fluctuated quite a bit from game to game. For example, Battle Network 4 had a very thin plotline overall, scattered around a silly tournament structure that featured tons of pointless scenes. They had the basic elements to make it a success (Worldwide travel! Killer asteroid! Judgement Day! Lord Wily's son!), but they couldn't quite get something interesting out of it. Also, the universe itself became a bit sillier as time moved on, such as everyone getting a new PET in every game (every few months in-universe!) for the sake of selling toys. I loved most of it, but it did show several weaknesses that could have been avoided with a stronger global oversight.