Some people seem to have problems, or even to forget completely to remove the protective materials. The individual toner have such backups and they must just stop to be removed before the first term or else you can hear just this weird noise.
The device has all kinds of nonsense like NFC etc. but what I have not yet used but it seems to be working well with my Nexus 5.
Cons should also mention yet:
1. Although I have made (the printer is in Germany) the environment to the highest moisture level the paper bulges after printing. I will test next very high quality laser printer paper with 100g / m2 and hope that it gets better.
2. replacement toner cost a fortune so I'll look around me better next purchase.