Cunliffe is more guarded. He exhibits a touch of political Aspergers combined with a propensity to over-ham the left-wing dramatics.
This overshadows his own very pleasant personality and sharp mentality.
But hey, he has to survive in a very ideologically-riven Labour Party.
Sure, Cunliffe has dressed McCarten's appointment up as that of a new "chief of staff" to take the place of his friend, the former legal counsel Wendy Brandon, who developed a persistent case of shingles after she left Auckland Council to manage the Labour leader's staff.
But McCarten is more Karl Rove with a touch of Heather Simpson thrown in.
Note the Karl Rove allusion.
Most observers have focused on McCarten's organisational skills. Sure, he does have organisational skills in spades.
No one survives as a key union organiser for such a lengthy period without having superlative skills in this vital area. And yes, he was the prime organisational driver for the breakaway New Labour back in the day when Sir Roger Douglas and his cohorts such as Richard Prebble held ideological sway within the Labour Party.
But that was a quarter of a century ago. Time moves on.
McCarten's strategic utility is not simply as an organiser.
In the same way that Karl Rove was George Bush's "brain", McCarten's key utility is to provide the strategic smarts and rat cunning that right now Cunliffe clearly lacks. With McCarten as his "left hand man", he can concentrate on being Labour's leader, confident in the knowledge that someone he trusts is running political operations for him.
McCarten's key utility is to provide the strategic smarts and rat cunning that right now Cunliffe clearly lacks. With McCarten as his "left hand man", he can concentrate on being Labour's leader.
The latest opinion polls show that Labour is not making any real purchase with the public under Cunliffe's leadership.
There's no real danger if McCarten occasionally overshadows the leader. He's already being comprehensively over-shadowed by fellow MP Shane Jones.
The problem is that the Labour leader still remains an enigma for many voters. For instance, within the business community there is still a lot of confusion over what Labour really stands for and what agenda a Labour-led coalition government would implement. Both Cunliffe and his finance spokesman David Parker are extremely personable in the boardroom context.
Business elites are pragmatic.
If policy changes are well sign-posted (even if they do not agree with the rationale) they will make pragmatic responses.
But right now there is still confusion over what Labour stands for. Will Parker for instance, make good on his behind scenes pledges to distribute a fully-fledged monetary policy paper for peer review before foreshadowing major changes to the Reserve Bank Act which could destroy confidence if not appropriately managed?
You would expect business people to take this stance.
But there is also confusion within Labour's own core constituency with the distinct possibility that the "battlers" who did not turn out at the last election - and whom Labour wants to zero in on - may not turn out in vast numbers at this year's election because they are doing fairly well in the current economic climate where confidence is at record levels.
Piercing this cloud of sanguinity will not be an easy feat to manage for Cunliffe and McCarten to orchestrate.
It will require exceptional skills in the dark arts of politics.
My pick on where McCarten will excel is in mounting spin patrol around the press gallery.
Cunliffe is not widely liked within the gallery. That was obvious by their coverage during the primaries for Labour's leadership vote last year.
But McCarten is a known prospect. He has good contacts with the commentariat who he has debated against and slagged off on multiple news mediums in recent years.
From first-hand experience I can attest to McCarten's debating skills on TVNZ's Q&A programme. He is a sharp and intelligent commentator.
He also knows how to zero in on an opponent's weak spot as I found out to my cost when he played the bloated plutocrat card on me the one time there was another cameraman in the studio filming him for a documentary on his life for New Zealand Story. He was theatrical. Accomplished.
I don't think his jibes made the final cut but he was not one to waste an opportunity.
Richard Prebble's organisational skills were also honed in the Labour Party where he was part of the "fish and chip" brigade that dispatched former leader and Prime Minister Sir Wallace (Bill) Rowling.
But again that's not the only reason Act has brought their former leader back to be campaign manager for the upcoming election.
Both McCarten and Prebble have battle scars from 25 years ago.
But importantly, they have the skills which are yet to be bred into those that succeeded them first time round.
