I think the popularity of these two exchanges is a lot. But it is seen that when selling any token in UNISwap exchange, gas fee is charged extra due to which small amount of tokens cannot be sold in this exchange. It can actually be sold but the transaction fees is more than that. But if a 1inch exchanger lists a token, its price goes up and there is no transaction fees like UNISwap exchange. That's why I think 1inch exchange is better than UNISwap exchange.