I'd say the Xbox One will sell more, even though it won't be out in Japan or some European territories by April (as far as I know).
Wii U has been selling a lot in Japan the last weeks, but I wouldn't be surprised if the sales spiral downwards to ~20k a week until DK is released. Wii U isn't selling in Europe and some of the games releasing in Feb/March will put the Xbox One further ahead in the US.