My preference would definitely be DAI, but if I had to choose between USDT and BUSD, I would definitely choose BUSD. Actually, they are the same thing, but behind BUSD is Binance, and most importantly, there is a strong character like CZ. Don't keep more in these shits than you can risk though. If you hold more, you are taking a big risk. Remember, centralized systems do not coincide with the idea of decentralized cryptocurrencies.