Top phone.

Advantage of FritzFons at a Fritz box is that you can see directly all telephone lists (incoming, outgoing and missed calls). To ensure that no numbers are there but just the name gets the Fritz box the phonebook directly using my Google Account, which is also on my phone. Other options would have been even GMX or 1 & 1 Web and phone books.
The data is updated daily to ~0 clock, so that new entries from the FritzFon the next day are on my phone. However, the establishment of the Google phone book is far from easy, since one purpose must disable some hidden features in Google for Accountischerheit (on [.....], by provide two-factor authentication to OFF and access for less secure Apps Enable).

The voice quality of the phone exceeds that of 10 year old A40 at worlds, but I honestly expected.
Connecting a headset is very easily solved with a 3.5 mm jack plug; the establishment of the headset comes with one pin and pull off without any problems.
Whether you need additional gimmicks like email, podcasts or RSS feeds on a home telephone necessarily I leave time to be seen, I do not use the functions.

All in all I give the Fon 5Sterne because absolutely nothing wrong with that. Strong buy recommendation.