I have 6ohm speakers and go back and fourth, the 'high' setting sounds good, more delicate, slightly better bass response, more detail and possibly better imaging. However the 'medium' setting has more dynamic's to it and has a certain warmth to it that I like, so it depends what kind of music I am listening to and what I feel like hearing at the moment. The one thing that I noticed is that the amp stays noticably cooler when it is in the 'High' setting, not sure exactly what that means, but I am sure what that means but I can only imagine that it is a good thing. Most of the time I keep it in 'High', but it really depends what you like to hear, try it yourself and listen to the difference. Cheers! Tim