After doing quite extensive research on this myself very recently, I went with Internaxx, which was bought by SwissQuote last year. SQ is also a good option. Alternatively Standard Chartered Singapore has pretty extensive ETF choices. Internaxx/SQ have both fixed custody fees, while SC SG has no custody fees at all, making it very attractive option. There is however 0.2% trading commission for priority banking (0.25% otherwise).
You can read a lot about Internaxx on Andrew Hallam's website, he also get some special deals for new customers, e.g. free trades or lowered fees for few months.
I did consider IBKR but decided against it:
- FDC $250,000 insurance seems to be valid on USD currency only
- complicated trading system (compared to Internaxx/SQ)
- estate tax risk for non US persons
The estate tax risk is complicated one and opinions vary, normally if you don't hold US stocks, US bonds, US domiciled ETFs, it should not apply but there are still a lot of questions and doubts about this. I am after Irish domiciled ETFs, but ultimately decided against IBKR.
There are however rich people who would trade via IBKR and transfer the positions out of IBKR. This transfers are free. So you can buy cheap and transfer them somewhere else for safekeeping, some brokers do charge a fee for receiving position transfer as well.
Banks have usually quite high custody fees (apart from the Standard Chartered Singapore mentioned above). Citibank UAE has 0.2% custody, Citibank IPB London has 0.5%. Julius Baer 0.3%, it can go down to 0.1% if you have like €5mln invested.