The best floor depends on your priorities.
Higher floors offer a nicer view and less noise from the street below. There can be more city noise emanating from further away. Temperatures can be hotter in the summer but with better breezes. North and east facing suites get morning sun. West and south facing suites, which get a hotter afternoon sun, can have higher air conditioning costs and lower heating costs. Fewer floors above reduce the likelihood of water problems dripping down on you. There is greater protection against break-ins since thieves prefer lower floors easier to access via stairs while avoiding security cameras.
Lower floors, above ground level, are less dependent on elevators. When elevators are crowded, out of order or reserved for moves stairs are a practical alternative. Traffic and street noise is less than for higher or ground floors.
Ground floors may offer a larger outdoor space. They are more accessible to those with disabilities or uncomfortable relying on elevators. With nobody living below, there are fewer adjacent neighbours. During an emergency, emergency services have faster and easier access to your suite. Windows and patio doors are at greater risk of break-ins. Area tree coverage provides greater protection against the sun.