I have used both Banks (HSBC and Standard Chartered) and exchange companies i.e Alfardan and Gulf Exchange. I have found the minimum charges and best coversion rates from exchange companies. Try to find to which back in Canada they deal with. The Gulf exchange company deals directly with Royal Bank of Canada and therefore since no other bank in involved in the transfer, you will pay minimum fee. If there is a third bank involved, they will also chare their service fee and you will end up paying more service changes in Canada.