I am writing for professional reasons a lot and was looking for a keyboard with which I can write without problems for a long time without the keys sounds nervous or I have to play keys repeatedly. I am very happy with the Logitech and can wholeheartedly recommend it! It seems well to give different versions, when I read through the reviews - so I find nothing to complain about on my part. The lighting is also comfortable at night and non-irritating to the eyes, and the function keys are not illuminated - but the signs are it (eg the play-sign or the home button characters). So is not totally dark.