Device is nice and flat, fits comfortably in your hand when calling. But no more than that !!!

I run to my Fritz! Box 7390 both a Fritz! Fon C3 and two Fritz! Fon M2. The Fritz! Fon C4 I bought because it is as flat as the M2. It is much better in the hand and the phone is much more pleasant than with the thick C3.
Very disturbing however is the noise and tweet the phone. Even at rest, it is clearly heard from the rear speakers.
Call does so not fun !!!
Therefore, only one star.
From the sound of her and of the background noise, the M2 is the best choice at the FritzFon'en.