Which is better for buying US stock DBS Vickers or Standard Chartered?

I currently have Tiger Brokers for small US trades but my friend advised that it was better to go with a bank-supported brokerage as there is zero risk of the platform going out of business or encountering problems. I want flexibility for bigger lump sum trades or small amounts (~1k) to DCA. Is DBS is $18 minimum fee for US trades OR 0.15% whichever is higher, or are both fees combined in one transaction? SC has higher minimum %fee but no custodian fee. Which should I choose? Or any other banks?