Endowus vs FSMOne vs POEMS vs Dollardex for SRS/CPF?

All the listed platforms are different kinds of investing platforms.

• Endowus is a robo-advisor, they invest using unit trusts and charge access fee but offer trailer fee rebates
• dollarDEX is an unit trust platform, and they are zero fee platform
• FSMOne is a brokerage platform that supports stocks, ETFs (which is a form of stocks) and unit trusts, they charge commisions for stocks, and for unit trusts they charge platform fees for SRS, but zero fee for CPF
• POEMS is another brokerage platform that supports similar instruments as FSMOne, and they are zero fee platform for unit trusts, but commission based for stocks/ETFs

For investing S&P 500,

• using CPFIS-OA, you can only invest in Lion Global Infinity US 500 Stock Index Fund thru Endowus
• using SRS, you can invest in S&P ETF (ticker: S27) listed on SGX, or Lion Global S&P fund