Personal experience.
I have used both city and swift at the same time, as my persnal experience says, you cant compare both, both are different.
At the end of the day, city will save some of your bucks in mileage, and for some (at some time, including me) mileage is everything, so they will go for city.
If you are talking about just comfort,
If there are 4-5 persons on board in any of these cars, and travelling for 200kms, believe me the rear one will need a break when you are finished.
City suspentions are stiff/hard. As using both cars at same time i can say that both cars are almost same in comfort.
But , at some times, iwill give advantage to swift comform. Just some.
Right now, im using swift, but i sold city. And yes, one of the reason of selling was the suspentions, stiff/hard.
Iwas not sharing my city experience here bcause the OP want swift/cultus review.
As my brother here asked so i mentioned.
These all words are mine experience and views.