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You know about the Garmin watches, right? They'll do navigation and (some) message notifications. Some reading: http://www.dcrainmaker.com/2014/11/winter-gadget-recommendat... http://www.dcrainmaker.com/2015/12/garmin-forerunner-630-dep... Polar, TomTom etc have similar devices, but Garmin are probably the default choice.
Thanks, I've used Polar HRM since the late 90s, and then switched to Suunto GPS-enabled watches. But I'd prefer something with a bit more features. Something that can replace very very casual smartphone use. Receive a short call, navigate somewhere. And track my fitness all the time, including HRM w/o band and blood pressure.
But no mainstream[1] smart watches can replace a phone - they act to supplement it
[1] I think there is an LG watch with a SIM in it, but it has limited availability.