Doona or mockingbird

So I live in Yonkers, NY but I travel to to the city a lot as both of our parents and friends live in the city. We don’t own a car, and take public transportation or Ubers but mostly transit. Having the Doona would be nice as I can easily load baby on and off without having to fold the stroller to get on the bus or take stairs for trains. But I’m in love with the Mockingbird as I already have a 3 year old, almost 4 when baby gets here and we still push her around in a compact stroller. I can’t imagine having to take baby out stroller, fold, and carry stroller when I need to take the bus/train. Also we do plan on having more kids closer in age. We do want to purchase a car but right now the car will have to wait.