What is the difference between buying S27.SI: SPDR S&P500 and buying a london/irish - domiciled S&P500 ETF? Which is better? ?

There is a really solid piece written by one of our writers here!
A Dummies Guide To Investing In Ireland-Domiciled S&P 500 ETFs: https://blog.seedly.sg/how-to-invest-in-ireland...

Singaporeans investing in the American market are taxed 30% on our dividends as the U.S does not have a tax treaty with Singapore. For example, if the company declares a dividend that amounts to $100 to you, you will essentially only receive $70. We are exempt from capital gains (when the share price of our shares increase).

One way to go around this is to invest Ireland-Domiciled ETFs. These Irish-Domiciled ETFs benefit from the U.S./Ireland tax treaty rate of 15% on dividends.

And while this is not perfect, it certainly is more pocket-friendly than 30%.