It's bad man.
Here's how.
1. In order to achieve this win, Microsoft had to deeply devalue the product they had been offering all year for higher prices. Consumers jumped in - with a big jump early in November - but according to insiders, Sony may have even won Black Friday and it was those early two weeks that allowed Microsoft to keep the overall win.
2. So, due to this fact, what happens? Will Microsoft have to keep the price at $349? I don't see any viable alternative if they want to stay even remotely competitive now. If they go up to $399, consumers are going to wait it out knowing Microsoft will take drastic price cutting measures if they feel threatened from a marketshare point-of-view. So they'd just as likely wait it out. Consider Xbox division is already under pressure to start making a profit and being a viable pillar, many interal debates between services & devices and the other divisions. In order to just barely win, they had to cut in deep to their profit margin.
3. This means that once the glow of the price change is over, the trajectory indicates it's very likely now PS4 is just going to go back to winning every month. This is the last thing Microsoft wanted. Now they've devalued their platform, their profit margins are diminished, and PS4 is still the marketleader getting their good PR. Microsoft gained almost nothing in the exchange, except perhaps to tell third parties planning to publish games in the West that it's still important to make ports for XBO and engage in marketing deals with MS for some exclusivity and other mutually beneficial deals.
4. With all the game announcements from Sony in December (in fact so many that PS4 is dominating December discussion, in a crucial period of the time when families come together and thus quickly spread their opinions on personal events, TV shows, games, etc), it's not likely Microsoft is going to have room to breathe to make a second month upset. Microsoft Store is selling their system at an astonishing $349 AC Bundle with two free games on top of it, but it will not be enough with numbers that look like this even for November NPD.
None of this means XBO is selling poorly, it probably did quite well if it's that close and edged out PS4. But it does now mean the future is clear: Sony has this generation in the bag in terms of system sales, including in US and UK, and that Microsoft is going to have a very hard fight to even keep their unit sales competitive in their only two remaining viable territories.
