Dai is a decentralized stablecoin which is pegged to USD through unique mechanism. Unlike other popular stablecoins whose value is backed directly by USD, it’s backed by crypto collaterals that can be viewed publicly on the Ethereum blockchain. Dai was created by respectable Maker company alongside MKR. Dai has solid user base and you cab buy it and sell it easily. The problem is only its acceptance as a token for exchanges like USDT is used. The competion in stabecoins is severe now and I am not sure if Dai has a good spot. It would be nice to see Dai as a main stablecoin.