I think about the same, but A Link Between Worlds just a bit more. I'd put MM3D at between 2.5m and 3m, A Link Between Worlds should end at 3m, and it's a bit undertracked here.
We'll see in march when Nintendo updates their million sellers list. OoT3D wins, could get near 4m. MM will probably have the biggest opening though, due to install-base, but won't have the legs because it doesn't have the legacy of OoT.







