It’s only a £50 thing, but it does notifications well and has battery life of about two weeks. It’s much better than the Android Wear watch I had previously.
Although if you just want to track a simple walk them Google Fit on your phone might be enough.
When I first started this the phone apps were fine for recreation and I suspect their features have only got better. They were somewhat let down by the phone’s GPS hardware though - you could lose signal if you were walking in thick woods, for example. I’ve got a purpose-built Garmin GPS unit which (apparently, I’ve never done a comparison) will hang onto the signal when a phone will lose it. This might be important if you’re out in the wilds and really need to know accurately where you are. It will also continue to work fine after you’ve retrieved it from a muddy puddle. This I can confirm.
Phones use GPS and also triangulate using wi-fi signals. This latter system is generally better than GPS if you’re in town, as there are tall buildings in the way and it’s very fast. But in the countryside it’s totally useless, so you only have the GPS. It’s rarely an area that they spend fortunes on when speccing the phone hardware.