I've been going through an amazing experience over the past month plus...purchased and began wearing an Apple iWatch. Never really thought I would do so...kind of did it on the spur of the moment. Plus a little push from my team lead at Oracle, who wears one and loves it.
Even after a month of wearing the iWatch, I can't really point at one particular feature that makes it worthwhile. It's really more a collection of little things that add up to big value.
One example: I have a reputation far and wide for being late for meetings (could be a Freudian thing, considering how much I detest meetings). 5 minutes before a meeting begins, my iWatch starts to vibrate on my wrist like a nano-jackhammer. My punctuality for meetings is much improved now, much to the joy of my managers, peers and customers.
Another example: I can take a phone call wherever I am, distraction free. That's right, calling Dick Tracy. Driving, taking a walk, whatever...we can talk now.
Notifications are wonderfully designed...much better than the iPhone or the iPad or the Mac or whatever. I've actually turned on Notifications again, because they notify without being intrusive or distracting.
A few other dandies as well, like the idea of getting through the security line with the iWatch is a bit quicker than the iPhone or the much-improved implementation of Siri making voice-dictation for texting something I can now user reliably.
So its improved my productivity... not so much by hitting a home run in any particular area, but through lots of incremental little improvements. Pretty cool wearable tech.