X1 will do much better in 2014 than Wii U in 2013, but the 2014 numbers of both consoles could be pretty close.
Wii U will have better exclusives and X1 doesn't have X360's advantage of superior multiplats.
PS4 will dominate and beat Wii U's lifetime sales everywhere outside Japan in a few months.
X1 will struggle to beat Wii U's lifetime sales outside the USA and UK.