TMC with this TOMTOM device works perfectly in Switzerland. In the USA it works fine too, but the reception takes much longer and the traffic jam messages do not contain any waiting times.

As far as I can see, it's the same price at Digitec too :) TomTom GO 620 World (6")

Internally, 16 GB are available.

The TomTom GO 620 will speak street names if you switch to English but you must select a voice that has that capability. For example, Jane is a voice but she does not speak street names. However, Serena does. Choose a voice that states "Computer voice - reads aloud street names." If you don't find any of the English voices on the GO 620 you buy in Switzerland you will have contact Support and ask them to download one or two voices that read street names. I had to do that after I bought mine.

spoken streets

Telephony, messaging and traffic data can each be activated/deactivated individually

In this case, the mobile phone should be able to connect to the car and TomTom. I guess it's about sending the different services (data, communication) to different devices.

I don't know, the holder that comes with the unit is enough for me.