I can't argue for or against as they both present pro's and con's. This article sides with the whole competition breeds innovation philsophy, which is great as I'm sure the online features would be nowhere near where they are now without it. Obviously it's also good for the aggressive price cutting that we're seeing as well.
On the other hand you'll only have to pay for one system, all your friends will be on it, there will be more games available to everyone and if every game is developed to take advantage of the one system then more games will match the quality of the few first-party exclusives that we're getting now.