I've seen what people do think about each ones risks and I personally don't see it like that.
Imo they are almost similar in terms of risk and ways of usage, maybe their liquidity differs, but thats not a crucial factor for me.
So my thought on them - I hold 70% usdt and 30% busd because I just don't want to miss better price (because bitfinex and binance prices are different).
Statistically I see better price on bitfinex more often so thats why I hold more usdt than busd