I've owned the Garmin D2 Air for one year now and can give a complete and honest review of it's abilities and disappointments.
If you want moving maps, you must step up to the Garmin Delta PX. I recommend the PX as that is the model with Pulse Ox and Heartrate sensors.
So the D2 doesn't have moving maps, but it has pulse ox and heartrate which is awesome in it's own right.
It does just about everything else a smart watch should do. Has plenty of exercise and outdoor activity tracking apps.
I'm not a fan of the text message automatic replies, I wish there was a way to type replies back.
But the aviation apps are good otherwise.