Have to agree there. I use a programme called Morse University, which by the sounds of it is Koch method based. It's excellent: within 2 days of using it I was already proficient in 5 letters (not including 'S' and 'O' which everyone always knows).
One of the most important things I've found is writing down the letter as you hear the sound, i.e. you must translate it directly without having to visualise the dots and dashes and then make a reference to that mental picture.