IN 2013:

the PS3 has sold waaaaaaaaaaaaaaaay more then the WIU...

IN 2007:

The Wii has sold waaaaaaaaaaaay more than the PS2...

IN 2018:

?????????

Is not easy, we are in 2015, and we don't know what will happen.

As for first, we don't know when PS5 will release. that's a important factor, of course PS5 will hurt the PS4 sales, so, will be a complete different scenario if PS5 will release in 2018 or 2020...

And the most important, we don't know how NX will sell. For what we know, it can sell more than the Wii, or less than WIU...

Any way, i think is a interesting question, what do you think?

I will go with PS4.

I think PS5 will coming in 2019, and in 2018 PS4 will still be at >10m...  i don't know how NX will sell, but i don't think will be at this level.

I personally think/hope will sell at N64 level, but with a longer life.

It seems like the NX may be close to ps4 hardware, and if that is the case, ps4 will win no doubt. It already has the major 3rd party support and the already built library. We know nothing on what gimmick (if any) the NX will have, but even then, a gimmick only provides a short hardware boost while playstation non-gimmicky consoles have legs.

Ultimately however, it is too early to tell, but the knowledge we do have isn't too kind for the NX

PS4, 2018 could be the peak year of the console.

More price cuts, Slim versions, more games.

No idea... will just have to wait and get some info on the NX first :/

Since the NX will be in its second year in 2018 (!), sales won't be that high (partly due to weak 3rd party support, partly due to people waiting for the PS5 / XBTwo). The PS5 will launch in 2019, so PS4 sales will still be strong due to strong first-party releases for its last year. So I think the PS4 will outsell it the NX.

NX hopefully Nintendo can make a great return with their next console.

PS4 for sure.

If the NX is the Fusion project and Nintendo releases both the home console and the handheld version, the NX will outsell the PS4. If we count only the home console version, the PS4 wins by a lot.

I can't see this happening, NX won't outsell PS4 in 2018.