Which platform is the best to DCA on S&P 500 ETF?

Hi guys , I would like to DCA into S&P 500 regularly & was wondering which platform is the best.
Currently considering 2 choices:
1. Standard Chartered Online Trading Account - Vanguard S&P 500 - VUSA
2. FSMONE Regular Saving Plan - ISHARES CORE S&P 500 - IVV

VUSA is Ireland-Domiciled and will save me 15% withholding tax.
FSMONE RSP only cost $1 per transaction per month and it will auto help me invest monthly.

I plan to invest around $1000 per month.
Any recommendation for me?
Thanks!!

There's few factors you have to consider when deciding on whether to buy into S&P500ETF.

Dividend witholding tax of 15% (Ireland) or 30% (United States)
Commission charges
Flexibility

For the first point, we cannot avoid witholding tax so we might be go for a lower withholding tax. However, I need to point out that although we might go for the Ireland one, you need to take note of the charges (commission charges) for doing that. Are you saving more money if you decided to go for the Ireland one but actually you have incurred more commission than if you go for the US one. Honestly, personally I won't bother much on dividend witholding tax and dividend handling fee if your main purpose of venturing to US is for capital appreciation.

Thirdly, flexibility. FSMOne RSP has a fixed date on when they will execute the order. You might not be able to buy at the bottom say March 23 2020 because it has been executed on the 8th of March.

Which platform is the best to DCA on S&P 500 ETF?

FSMOne Fundsupermart

Standard Chartered Online Trading

Moomoo Singapore