Hello.
I've just sold my Vista. It isnt even anyear old. 
In a nutshell, it was too big, too heavy, too clumsy. I also live in The City and it just wasn't feasible. The pavements in my area are pretty awful - uneven, lumpy bumby, hilly, just all over the place, with the added annoyance of cars parked on the pavements meaning I regularly needed to bump up and down the kerbs.
It was used as a double. It was so cumbersome, I mistakenly believed that once my toddler was old enough, i could do away with the Rumble Seat, fit a buggy board instead and then it'll all become a breeze.
I was wrong, and the Uppababy PiggyBack board had me cursing the day it was made. I kept kicking it because it got in the way of my stride. I'm 5"4 and not particularly leggy. It would have been better for me if the handle bars extended furrher away from the the pushchair, and therefore closer to my body meaning the board/pushchair wouldn't get in the way of my legs. The problem was/is that the shopping basket is long. It's parallel to the handlebars, so add on the length of the board and that was why I booted it every time I walked.
It's so bloody heavy. So heavy. However its a dream to push with one child in it. Really lovely. Like the Bentley of pushchairs. However, Once another child, the seat unit and shopping is added..? forget about it.
And whilst I'm at it, there's no point for a huge shopping basket if, once filled to the brim because of taking advantage of its size, you can then barely move the Vista round the streets and up and down kerbs. The chassis and seat are over 12kg, the rumble seat, about 3kg, a toddler, a baby, shopping, changing bag..I'm not a particularly weak thing but I hated it.
Anyway, you're in the city, using public transport every now and then. Do yourself a favour and go with a compact pram. Its horrible to be so sorely disappointed with what you thought was the perfect choice, and also having to put your hand in your pocket all over again.
I'd recommend items like the icandy raspberry or Strawberry2, the Cruz, Oyster2, and there's a few others I forget the names of now. I'll try to remember.
The Vista is luxurious but it's a real workhorse. I don't think you should bother.