According to GAF, MH3U's combined numbers are about the same as Tri's debut on Wii.
I'm surprised that the Wii U version came so close to the 3DS version in terms of sales, though considering that there are supposedly heavy shortages of the 3DS version (with Shopto making some cockups with my friend's 3DS version as a result, giving him a Wii U version instead!) I shouldn't be really...