We don't know who sold more, but I think they were both successful.
What we really need is official, first-month figures from Sony and Microsoft, but realistically we’ll probably have to wait until after Christmas (the inflated sales from the holiday period are just too juicy, as far as the PR and marketing departments are concerned). While Sony was promising a large second shipment of consoles before Christmas, it seems it never arrived. Over in the UK, a Sony executive says that it’s sending a steady stream of smaller shipments to retailers, which would explain why some stores show the PS4 in stock for a few minutes/hours, before quickly selling out. Again, though, without hard data from Sony or Microsoft, we can only really guess at the situation in the US and the rest of the world.
I think this problem happened in America, too. It may be selling better, but both systems are doing well.