NPD is fine as a benchmark. It doesn't give true numbers but the sample size is more than big enough to make it significant.
What would be a better judge of who is "winning" would be if you had access to all the financials. e.g. Sony were taking a bigger hit out of the gate on cost but then MS slashed bundles with Titan Fall and looks like xbone has a slightly better attach rate.
The press should not be afraid to point to the figures and say that Sony is doing better in sales but then the NPD thread is full of people on the other side declaring that the war is over just because xbones are moving 30% fewer units. The same people likely declared the PS3 dead in the water on release too.
What would be a better judge of who is "winning" would be if you had access to all the financials. e.g. Sony were taking a bigger hit out of the gate on cost but then MS slashed bundles with Titan Fall and looks like xbone has a slightly better attach rate.
The press should not be afraid to point to the figures and say that Sony is doing better in sales but then the NPD thread is full of people on the other side declaring that the war is over just because xbones are moving 30% fewer units. The same people likely declared the PS3 dead in the water on release too.