Should I buy a newer model?

willi1936 Registered Users Posts: 1
New Traveler
edited January 2019 in Pre-sales Questions
I have a 6 year old GO750Live that was not updated the DACH Maps since 2013 or so because both BMW and Tiguan now have built-in navigational units. We go to the US yearly and pay dearly for GPS rentals so the question: should I update the old unit with the US lower 49 states Maps or buy a newer model (which?) with those US maps.
I must add that due to high roaming costs I will not use my Swiss iPhone in the US - a US friend is loaning me a spare regular cell phone for the duration so I will be able to communicate but not with the GPS of the TomTom.
Any advice as to model, whre to buy - in Europe or the US, or to upgrade my old unit?