GPS Recommendations for South America

Hi, all! We are currently researching GPS systems for our upcoming travels and wanted to see if anyone has any advice or info on the best GPS/favorite models/etc. We've tried searching via Google and since a lot of the results are a bit outdated, it's probably best to start fresh here. All suggestions are much appreciated! 

Garmin map upload

I'm travelling accross Americas with my family.
I have a GPS Garmin Nuvi 1350.
In my computer I have all the Maps from Mexico to Chile but I don't know the process to transfer it on my Garmin?
Is there someone who can help or send me the procedure?
Thanks a lot.

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