the +: price, lightness, less than 10 cm long (for those who do not like large) 6 buttons, sensitivity adjustment on the fly, the air quality sensor. works without driver Linux (pclinuxos).
the -: plastic "cheap", wobbly (pads not all rise: a tinker) buttons "side" but not under the thumb under the index.
Summary: for 10, have for money, but this is not a Logitech eh!