ABEI the connection was rather marginal with the 600 model (30-35mbit). The AVM 1000 unit I had also tested, but the part went not at all times. It sat regularly but had minimal better sync. Useless returned.
The 1200 devolo had a tick better sync, but the connection was at least also very robust, even at full throttle the connection. (Ca 45mbit)
recently there was a firmware update and now I'm rich 100/83 Mbits and very robust connection ....
1a! I bridge the way about 2 electricity meters away in a high-rise, from one apartment to another, where it works with only just 2 sockets! 8th-)
Firmmware update bring people! On the devolo website!