We decided to hold off getting a PS4 or Xbone – early adopters always get shafted. The price drops massively in the first year or so (in the case of the Xbone, within months), and early machines always have those little niggles (red ring of death, yellow light of doom, etc).
Instead, we got a Wii U (well, technically it’s the husband’s, I bought it him for his birthday) and it’s amazing fun. There isn’t a huge number of games, but the ones that are out are amazing, plus there’s more on the horizon (like Bayonetta 2, but that’s probably not for the OP’s daughters).
It’s great for multiplayer action – I really can’t recommend Mario 3d World enough, and that’s from somebody who traditionally has been a bit ‘meh’ about Mario games. Another big advantage is that it’s backwards compatible with all of the Wii games, so that’s a lot of additional games. Let me know if you want a copy of Bratz: Girlz Really Rock or Spongbob Squarepantis Atlantis… 😛