Everything has it's place. Bradford Pears supply brief springtime beauty, they grow fast, and for urban areas can provide vegetation in a relatively short period. Red Oaks and Shagbark Hickory are much more substantial. Sturdy, great hardwood, but they require a lifetime to grow to a semblance of maturity. With this shade and beauty, come clean up in the fall, and dead limb pick up after substantial winds. Red Oak pollen fronds can be substantial in the spring.
As for invasive species, the label also applies to Mute Swans, and Purple Loosestrife. Two of the most beautiful things that nature provides. Investigate and observe before applying the label.