Have just installed this and am pleased to say that it makes a noticeable difference to the sound when I am using headphones. Although the sound was already quite good to my ears it now has more depth and range to all music and sounds. I have not changed any settings from the default regarding bass etc, but I don't think I will.
The download is only 6.44MB and unzips to 1 exe of 6.96MB. After installation there is a very simple and easy setup routine to go through, then do a test with music, video or a game and hear the difference. No registration step as it comes already as a full version and not needing any further steps. Very easy all round and does sound better on my system.
So grab it while it's free and try it, if you don't like it then there's no harm done. :-)