I recommended Swissotel the Stamford.
Just right above City Hall MRT and they have connecting room.
The room is big and clean and the breakfast is yummy.
I've stayed at Swissotel the Stamford this summer. The hotel is a bit old, but with very good location and service. Moreover, the room are big enough to accommodate us (2 adults + 2 kids) with 1 extra bed added free of charge. We have booked a connected room with another family. The hotel rooms have been renovated this year (but I think it is just replacement of some items only). The breakfast with choice of 2 restaurants are very good, too. One more thing, remember to request high level floors, as the views and impression of the rooms are significantly different.