Once and never again!
That was also my idea about moving house... but at both places of residence the data rate was so massively lower than the advertised 300Mbit/s that the product was unusable. I then connected to the Internet via my cell phone hotspot. 'iot Daten Flat' goes via the Sunrise network and I would think twice about whether I wanted to do that.
Oh yes, the support is really bad, there is no feedback on the extremely low data rate measurements.