I love my bob, is comfortable to push and takes curbs well. When I go with it I take a small bike pump (one designed to attach to a bike to refill tires while you are out riding) and I typically inflate the tires in the morning and don’t have problems throughout the day. It works well for larger kids (4 or 5 year olds) who need space. The storage is easy to get to and holds a lot!
Now the negatives for the BOB, it’s large, does not collapse well for use on trams, buses, etc. - to the point that I’ll walk back to my car instead of taking the tram at the magic Kingdom.
I also use and love my city mini, if I didn’t think my 6 year old may want to use it I wouldn’t hesitate to use this one next time as my 19 month will be the primary passenger. It folds better and you don’t have to worry about the tires. Negatives include it’s a little less comfortable for larger kids, the underbasket is harder to utilize and does not hold as much, it does not take curbs anywhere near as well as the BOB...
All that said for kids in the age range you have unless they are on the big side I’d lean towards a city mini...