TransferWise

Super Cheap, quick execution and hassle-free. Perfect.

Super Cheap - it is really a saving vs. all other banks or transfer services (e.g. HiFX)
Have not found anywhere else where I get so close to interbank rate.
Quick execution - for me: I did the transaction in the evening, transfered the money in the evening. My money got exchanged and sent out on the next morning.
Hassle-free: I did not need to send any documents to transferwise: Just register, and you can use the service.