An apple is not better than a carrot. You cannot compare NoC with SoC because a SoC is the whole system and a NoC is an interconnect (network on chip) that could be part of a SoC but isn’t required. Complex systems can benefit from a NoC for easier layout, extra features like controlling different power domains and catching an access to a powered down part of the chip. Hence NoC can be part of a SoC, that is the conclusion here.
Which one is better NOC or SOC?