POSB Debit Card (Orange Colour) one works well for me.
The Nets pre-set limit is at $2,000 as the same like normal ATM
card, but I think you can sign up (signature based) to $5,000 up of
amount provided you have the amount inside. (correct me if i'm
worng) - This card I think they charge $18/$28 per year for the fee
after the 3 yrs free fee waiver promotion when you sign up for this
card, it's a Master Card btw so generally it shouldn't be a
problem.
So far the debit card has not given me any problem, I believe if
you have any problem, you can just request a change of card via a
call.
POSB GO Card (Blue Colour) is just a normal card, you also can
sign and pay using this card, but the weakness of this card is that
it's isn't recognised by online transactions.