This keyboard is used with an HTPC. The backlight is very significant for this use, as well as the click button on left hand side. Autonomy is good (I charging 1 time per week, while the whole family uses it). The keys are nice and not too small. Like all compact keyboards wanting (even if it is not really), my arrangement of keys on the right is not classical, and the "enter" key is not very big: it is a bit disturbing and it forces to think when you have to delete characters, or top of an excel table. The touchpad is a bit small for a utilisaition "office", but when you take the keyboard with 2 hands (standing or slouching on the couch), it's more convenient to sweep the entire screen with one touch the thumb. And since it's my primary use, it suits me.
The price, however, is a bit exaggerated. But Logitech advantage of the few products really suitable for use "sofa" (the K400, which I also tested, for example, is not backlit, making it unusable with a HTPC).
I recommend this keyboard, because they have found better.