They do charge on withdrawals, there is a withdrawal fee of $2 or $3, (im sure it was $2 but i think they sent a message advicing that fee was raised to $3)
For the me the debit card works fantastic, i even got better exchange ratio in stores than in ATMs, and never had any problem buying with it.
For online use you have to use the virtual card, not the plastic electron.
Cheers
ps: and yes, Michael deserve a mention, he is very helpful if you contact him with any issue.