This might seem obvious. But for us coming from Asia, it might not be obvious enough. To give you an idea:
I changed SGD$5341 to € at the airport in Vienna. It turned out to be €2883.07, but they gave me €2479.44 back, the difference being their commission of €403.63.
That's painfully high, and excruciatingly painful. Perhaps I'm more outraged by the fact that rich or poor we pay the same, and the financial industry should never take advantage of less wealthy folk like that. I had too much on my mind before coming over so I didn't change it back in Singapore. If you're coming to Vienna and Europe from Southeast Asia, definitely change your money in Southeast Asia.