I can only assume that those who give this bad reviews are using it incorrectly. It is directional, as it says in the instructions - hold it at 90 degrees with the logo and switch facing away from you.
Anyway, for me it's robust and effective and I bought one for a friend! If you're a gentleman of a certain age and suffering with that pesky ear foliage, this is perfect!
This is misleading - as another reviewer has said, this is not a 2680mAh battery. Look closely at the label. It says 3.7v, 5.25Wh - the same as others listed here. Using those figures you can calculate the true mAh: