I used to have stand-alone TomTom units, but I haven't used mine (for driving) for many years now. I still use it for planning, as it's very easy to select waypoints. I store the ITN file, then load it to my phone, which is easier to use for driving.
My phone is a better sat nav than a stand-alone unit.
Google Maps (free) is superb, especially if you download maps before going somewhere out of cellphone signal. I navigated out of the Serengeti when our guide got us lost. He was gob-smacked when I was took him down a track he had never used, and I said "just round this next bend", then straight in front of us was the back gate to the "hotel".
Waze (free) is the best if you just want to go to a single location. Post code in, route found, traffic avoidance happens automatically, hazard alerts are really good. I've never beaten Waze on route decisions.
TomTom (£20 per year) is quite good if you want to do itineries and route planning. Lots of online software can produce ITN or GPX files (but I still use my out-of-date TomTomXL), and these can be loaded into TomTom. I don't like it for anything else than planning, but I will use it if I have to. I buy it when I need it, then let it expire.