Completed my first USD transaction with this account. Am pretty happy with it so far.
A couple of things I noticed
1) When depositing a USD cheque, according to the counter staff, you *must* indicate (USD) behind your account number if you want it to be credited to your USD wallet. Failing to do so, it will be deposited into your SGD wallet instead.
2) You can easily change the daily limit on the debit function via internet banking. So, you can lockdown the card with a $0 limit, and only raise it when you're planning to buy something. You will need both your phone and 2FA security token to raise the limit by internet banking.
3) By internet banking, the maximum spending limit you can set is SGD5,000
(SGD0; SGD500; SGD1,000; SGD2,000 are other options available).
4) By phone, through an operator, the maximum 'permanent' limit you can request for is SGD10,000. It is also possible for you to request for a a higher 'temporary' limit (which will then revert to your previous limit) as well.
5) The 'spending limit' display on internet banking seems to only reflect the SGD wallet at this time.
That said, anyone who plans to use this, should keep in mind that debit cards are *extremely* high risk. Anyone with your card information can effectively reach into and take cash directly out of your bank account. I would only use this card on sites that I trust to keep the card information secure (eg: PayPal), and I would probably avoid using it at most other merchant sites.
Depending on how you plan to use this card an account, keeping a $0 SGD balance might not be a bad idea either (it will ensure all transactions use the correct FX wallet, or decline the transaction if there is insufficient funds) - only thing you'll want to make sure is you have enough FX to cover the minimum balance to avoid the fall-below fee.
What I would really like (which the account doesn't appear to do yet at this time) - to send an sms or email alert for every debit/ATM transaction.