Depending on where you live in the country, particularly in southern states heating would probably be preferred and radiates a lovely warmth. In warmer states and in summer down in the southern states nothing is cooler.
Some home owners design there houses using energy efficient techniques iusing a combination of large double glazed windows on north facing walls and using dark aggregates in their concrete. The concrete absorbs the rays of the sun which takes the sting of cold out of the slab in winter.
In good conditions and if the sun can reach long stretches of the slab it will actually become warm and hold its heat for a time.
Carefullly designed eaves on the outside of the house can ensure the slab remains in shade during summer time while allowing the sun to warm it during winter when the sun is lower on the horizon.