We already know that XB1 has a snowball's chance in hell of comparing to the PS4.
http://plebegaming.wordpress.com/2014/07/17/let-it-go-xb1-cant-compete-with-ps4/
The real question is "Can the XB1 hold on to second place going forward?" The Wii U had a strong showing, but it's going to go domant until September with no games. XB1 could grab a good bit of ground in these doldrums, but the Wii U has a smattering of coming titles that appeal to the Japanese, and Smash will reach a global audience. Not to mention the "looming amiibo".
The two biggest bombs MS had left were the price drop and the Master Chief Collection. The price drop fizzled out and HD remasters have never sold as well as their originals. Halo used to be King FPS, but it has since been convincingly dethroned by COD, which also has a launch window one week before the MCC if I recall correctly? Multiplats are where XB1 is suffering and the only thing it has that Sony isn't doing better is possibly the MCC.
Nintendo on the other hand isn't going for the same audience. Once again they're going for the casuals, kids, and Nintendo faithful this holiday. It looks like they're trying to claim almost exclusive control of the smart toy market by having the hardware built in. If they can make it so you don't have to pay for peripherals to enjoy the smart toys, they could entice third parties to get in on the action. If the amiibo does acceptably well, I can only imagine launching a line of smart toys without having to design and push your peripheral makes the Wii U seem more appealing launch pad for joining one of the fastest growing markets in electronic entertainment.
So can XB1 manage to outsell the Wii U going forward, or will Sony and Nintendo act as a sort of tag team to put it down to 3rd or 4th?