PlayStation 4 is still doing great, and is maintaining a healthy distance between itself and its main competitor, Xbox One. It's doing especially well in mainland Europe and Japan, but there is in fact a major region where the tables have somewhat turned - Latin America (mainly Mexico, Brazil and Argentina).
This was reported by Gearnuke who states that during 2014 Xbox One did in fact outsell PlayStation 4. And considering that it's the world's third largest gaming market and the second fastest in terms of growth, it might prove to be important if Microsoft can keep it up.
The main reasons for this are a very strong brand, and lower prices. Last generation Xbox 360 had a market share in Brazil of a whopping 85%, something made possible by it being almost half the price of the PS3. Microsoft is manufacturing the consoles in Brazil and can therefore avoid very expensive custom fees. During this year, Sony has started manufacturing their own consoles in Brazil to avoid this as they aim to become more competitive.
Thanks, Neogaf