I stayed at City Square for a month and had a great time.
The Online reception team responds to every question very quickly and the apartment itself (Apartment 9 on the 5th floor) is beautiful and spacious. The roof top terrace is the perfect place to watch the Sunset or the action at Tivoli Park during the day and you can reach everything by either bike or foot in less than 15 minutes.
I can only recommend this apartment to everyone looking to stay in Copenhagen for both long and short stays.