tomtom or garmin sat-nav?

At one time I would have gone for TomTom, as Garmin had out dated and less sensitive GPS receivers, they gave little or no information about their products and had limited features compared to TomTom. However current Garmin sat-navs have comparable or better GPSRs that receive from multiple constellations of satellites and have comparable or better features, in my opinion, for me though the outstanding feature of Garmin sat-navs is the ability to install non Garmin maps on their products such as the free Open Street Maps etc, I don't think this is possible with TomTom products. Oh I almost forgot, I still own a TomTom that randomly turns itself on without the user knowing, this destroys the internal batteries, as they are constantly being 'flattened'

BTW

I'm assuming that the OP is referring to a choice between TomTom and Garmin sat-navs rather than general GPS devices as TomTom primarily produce sat-navs, I can alter the thread title if you like

 

Garmin recently released new maps for Nuvis etc, so if your 55LM didn't come with version 2016.20 you will be able to update it using Garmin Express, there is a link in the Garmin FAQs (See link below) :-
http://www.gps-forums.net/threads/garmin-faqs.46082/#post-225280