Ether is surprisingly small and light, and does what is was designed to do.
It works well with headphones (A-T ATH-M60x), but when attached to a portable recorder (Tascam DR-22WL, phone) a constant hum is always present. Maybe changing the length of the connecting cable will help.
Also, the case is made of plastic, and to replace the batteries one must unscrew 4 screws - hopefully the batteries will last long, or the screw holes will not!