I'd be happy to sign the Auckland left back. He has looked really solid.
Aside from that no one has stood out too much... not diminishing them as players, just I think their strength has been the way they have worked as a team first and foremost.
Case in point, man for man I'd say Welly has the better back line, but based on current form I'd probably rather have the Auckland back four.
Both fullbacks Berlanga (Spain) and Iwata (Japan) have looked decent, as has Dordevic from Serbia who's on loan from a Serbian top flight club.