I had the chance to try out the Baby Jogger City Mini last weekend. Don't be misled that this is a jogging stroller for any significant speed or distance, but it was great for going around town. First, it folds up so small that it easily fit in the back of a closet. The wheels are not inflatable so you don't have to worry about flats, but there is still a good harness, unlike an umbrella stroller. My kids can squirm out of those in no time flat.
The swivel front wheel and tiny tires that I complain about for suburban jogging proved invaluable for the shimmy between inner and outer doors and making side-to-side maneuvers while going up curbs. I jogged briefly. The swivel wheel gets a little wiggly, but the bigger problem is that the handlebar is very narrow. Perhaps a perfect candidate for healthy handles!