To me, they serve two different needs.
Xbox LIVE provides a stable online multiplayer experience with superior cross-game, chat, and messaging functions. Nintendo Network provides an online community that's far more satisfying on a social, artistic, and creative level.
So, if you want to play games online with people around the world, you want Xbox LIVE, price notwithstanding; if you want to share your experiences, achievements, and ideas with people around the world, you want Nintendo Network.










