Good sales for the PS4, although if it did sell 550k+ units that would be higher than most people's predictions which concerns me a bit. While selling this fast is good for Sony it also means the PS4 market will be saturated much faster. Just like how it broke records at launch but after the hype died down, sales crashed and it sold under 200k for much of the year.
Thinking more about this it's really similar to the Wii vs. 360 situation. The Wii started off cheaper and more popular, but eventually everyone got one and lost interest. The 360 eventually caught up in America even though the Wii was routinely outselling it 4-to-1 in 2008.
Right now the One has more room to cut price (cheaper parts and bigger war chest) which means it'll eventually be cheaper, and its big hitters like Halo 5 and Gears are still to come.
The PS4 is doing great now but there's no way it'll be able to sustain this kind of momentum. I'm curious to see how the two consoles perform in 2016.