It's not an easy question to answer these days - whether, if they could, the All Blacks would swap Aaron Smith for Will Genia.
Actually it probably is - they wouldn't. Perhaps it is not permanent, but for now Smith looks like the better player.
He's just as quick and dangerous around the fringes. His passing is better. His aerobic capacity is the equal of Genia's, his kicking about on a par and there doesn't seem much difference between them in terms of tactical vision and play-making authority.
Smith won the battle of the number nines in Sydney and again in Wellington and he'd have a reasonable claim, for now at least, to call himself the best halfback in world rugby.
Which is not something he or anyone else thought they would be able to say a few months back when his form for the Highlanders was borderline horrid.
There was even talk back then that he shouldn't be in the squad. But the faith the selectors showed was a vital part in his renaissance, as was remembering that in the All Blacks, he has only to focus on his core role.
"Coming in this year you are not as nervous," said Smith in regard to how much more comfortable he is in his second test season.
"You don't want to be late to anything. It is a bit different, but to be honest I was just pumped to be in there [All Blacks] given the horror I was having in Super rugby.
"The coaches had a lot of confidence in me and that really helped my confidence in turn. I really had to get into that mental state of mind where I just did my role and play what I see.
"We have put a lot of pressure on ourselves this year to raise the level and that has helped my game a lot."
It's also helped him immeasurably these past two weeks that his forward pack have been well on top. Life behind a dominant pack is a different experience and possibly it's not fair to judge Genia given he's been stuck behind a pack that has played with only two gears - neutral and reverse.
Smith, by the second half at least, was afforded more time to make his decisions. He had more space to exploit around the fringes and more momentum to play off.
"It is awesome to see that kind of effort [from the forwards]," he said. "It is a good: there is no better feeling than seeing our pack walk all over theirs. It is all about roles - we want go-forward ball. It makes everything better: makes the game flow a lot better and once we got our ball carrying down and weren't rushing things and were making the right decisions, it was easier [for him]."
As impressive as Smith was, a better, or fairer test of his standing in the world game will come when the All Blacks meet the Springboks at Eden Park. The South Africans will be a different proposition - robust, strong and aggressive, they will hold their own up front and put the pressure on the All Black decision-makers.
Smith will relish that. Partly because he's the sort of person who enjoys being put under pressure and partly because, strangely, he feels he needs to make amends for his performance in Wellington, which he says wasn't up to the standards he has set for himself.
"I am not very happy with my performance," he said. "The kicks were too long and inaccurate, I got caught a few times and I slipped a few tackles. I have got to keep striving for perfection."
