Does anyone have any reviews on FSM RSP?

Hi anon,

Dividend withholding tax of 30% needs to be paid if you are RSP-ing into anything that's listed on a US exchange, after you declare with the W8-BEN form that the beneficiary owner of the amount received from U.S. sources is not a U.S. person.
You should also examine your transaction costs to see if it makes sense. You will likely incur custodian costs as well.

If you were RSP-ing into a UT that tracks S&P 500 (e.g. Lion Infinity Global Stock Index), then W8-BEN is not needed, and there should be no transactional costs nor platform fees.