It makes weird noises when it's inserted into the mains, and especially when it's charging.
This makes me afraid it could damage the connected devices (or catch fire!), thus I'm worried about using it.
Besides, when I connected my Kobo Glo e-reader to charge it, the first time it did charge, but in the end the e-reader was frozen (after a restart, though, it was charged and working fine).
The second time I connected the Kobo, it didn't receive screen touches/commands, and it kept going from charging screen to menu screen (on its own).
Please notice that, when I connect the Kobo to (and charge with) my computer, it works flawlessly. Thus the charger seems malfunctioning (at least partly).
- UPDATE 9/12/2013
I contacted the customer service and they promptly apologized and offered me either a refund, a bonus coupon or a replacement.
Although it's annoying getting a faulty device, it may happen; when something goes wrong, I know I can trust this company to offer an outstanding customer service.
I'm really pleased and I will shop here again.