XBOX LIVE problems since Christmas?

Is anyone having a hard time logging on to XBOX Live lately? I can get a connection intermittently and I know for a fact that my network is up and running. I had just gotten the XBOX back from MS after having the Red Ring of Death repaired. It could be that they had a firmware upgrade or something that is causing the problem. Before I call and go through their voicemail tree I’m looking for similar situations or solutions.