I think you TT the $$$ to US brokers and trade is better than letting CIMB earn your "currency conversion" at a premium

DMC (danmooncake) mentions before he uses TD Ameritrade, OptionExpress, ScottTradeOption First and MBTrading.
Best you ask the man himself.

I use US brokers directly (ScottTradeOptionFirst, OptionExpress, TD Ameritrade, and MBTrading). Many of them are online and you can apply directly and submit your documentation later by mail. I kept all my trading currency in USD, so no conversion needed and I don't plan to repatriate my money unless necessarily need them (like big purchase, future retirement, etc....).

I'm active trader and I can't depend on local banks/remisier to do the transaction for me. By the time you let them execute your
trade, the price action would already made its move. Split second decisions, no second guess. Besides my late evening work allows me the flexibility to trade with US timezone. 

Well, there where two major crashes when I was in market. I've survived the dot com bust in 00/01 and housing bubble crash in 08/09. 
My portfolio took quite a beating in 00/01 but in 08/09, I rode the bear and bulls later when it recovers.
Everything came back more than double.  So, no fear. 

That is what SIPC is for.. if the broker bankrupt, you're guarantee for all the shares (amt not worth) that you've bought.