Basically the battery drains in two-three days. It’s a known problem and Garmin are trying to fix it. Very likely software as replacing the device made no difference.
That sounds like my experiences with the fenix 3 in the first year of its release, I persisted with it and eventually Garmin sorted the firmware out and it was fine from that point onwards.
In addition to maps, onboard music and garmin pay, There are a couple of other small things missing from the instinct that the fenix series do have:-
– instinct cannot estimate your Vo2 max
– instinct cannot give you an estimated recovery time
– instinct cannot be paired with a power meter, but it can still be paired with chest HR strap, cadence and speed pods.
– instinct does not do multisport within a single activity – eg a triathlon. you can still stop one activty and start a new one though.
none of those matter to me, quite happy with the instinct so far
All the other stuff I used to do on the fenix 3 works great:-
– customisable activities, allowing you to select and view different data fields for different activities
– display/navigate a route
– race a previous activity
– intervals
– metronome
– alerts based on customisable data, eg beep/vibrate if speed > x
– read text messages etc , and reply from watch
Its early days though, so maybe the curse of garmins disasterous first year firmware releases will also affect the instinct.
I expect the instinct is canibalising sales from the fenix range, I’m surprised they released it with its sports functionality so close to the fenix range.