In one goal you have England's best 'keeper in Joe Hart, and in the other Petr Cech can rightfully claim his place alongside Peter Schmeichel and Edwin van der Sar as one of the Premier League's greatest goalkeepers.
It is a toss-up to decide between either of them, but I would go for Hart on the grounds of his return to form since being recalled following his spell on the sidelines.
There were times when he came too far off his line and gifted goals to the opposition – the defeat at Chelsea being one obvious example.
No goalkeeper in history has gone through his career without having a bad spell, however, and Hart has taken stock and emerged through the other side to the extent that he has not made one mistake since returning to the team.
He gives his back four reliability and that is crucial.
Cech has given Chelsea that same consistency for a decade and, although he has shown a weakness in dealing with crosses, you cannot overestimate his contribution to their successes.
At his best, Schmeichel was worth 12-14 points a season to Manchester United and Cech has had similar periods at Chelsea.
If you had to pinpoint a weakness in City's armoury, it would be the left side of their defence.
Vincent Kompany may be the best defender in the Premier League, but the deficiencies around him could ultimately cost City dear against the best teams.
I am not convinced by whoever partners Kompany, whether it is Martin Demichelis, Joleon Lescott or Matija Nastasic, while neither of the left-backs – Gael Clichy or Aleksandar Kolarov – is top-class.
Kolarov will give penetration down the left when he bombs forward, but there have been numerous examples of him being 90 yards away when the ball has ended up in the City net. Sooner or later, that frailty will come back to haunt City.
If I had to choose a back four to keep a clean sheet in a crucial game, I would take Chelsea's.
They play in a totally different way to City in that they are prepared to defend the 18-yard line. I cannot imagine City ever doing that.
John Terry has had a fantastic campaign and their success in grinding out 0-0 draws at Old Trafford and the Emirates this season gives a clear indication into how Chelsea will play against City.
Jose Mourinho has managed to instil team discipline in midfield and, as a result, Eden Hazard and Oscar have excelled this season.
They are now prepared to work almost as hard without the ball as they are when they have it. So, when City are driving forward with Yaya Toure and Fernandinho behind the more advanced David Silva, Hazard and Oscar will do what is expected of them by getting behind the ball and confining the space.
Chelsea's advantage is that Hazard and Oscar are so comfortable on the ball that they will be able to keep it and give their team some respite. They are also capable of hurting City in an attacking sense, with Hazard, in particular, having as good a season as anybody in the Premier League.
What Chelsea lack, however, is the sheer power and driving force that City get from Toure. Ramires will run up and down the pitch all day long, but he is not as powerful as Toure, who is unbelievable both on the ground and in the air.
Fernandinho is also strong on and off the ball and he contributes to the sense that City play with the philosophy that they will score six if their opponents score five.
For Chelsea's game-plan to work at its best, they need a centre-forward who can hold the ball up and this is where they have a serious weakness. Nobody knows why Mourinho failed to sign another striker in January because the options he has available all have their failings.
Samuel Eto'o scored a hat-trick against Manchester United, but he has done little else, while Fernando Torres has been poor again. And Demba Ba is clearly not even in the picture.
City, meanwhile, have an embarrassment of riches to the extent that Edin Dzeko, a player who is not a regular starter, continues to extend his phenomenal scoring whenever he is called into action by Manuel Pellegrini.
The key to any successful team is to sign players who are better than those you already have and the acquisition of Alvaro Negredo proves the merits of that policy, having had a fantastic first season in English football.
City will obviously be weakened by the absence of Sergio Aguero, but they have scored goals with and without the Argentinian this season. Aguero is a world-class striker, though, and he has improved at City during his two-and-a-half years at the club.
(© Daily Telegraph, London)