It's hard to understand the value of this unless you use one. I frequently used to miss text messages, or even phone calls because I wouldn't feel my iPhone vibrating in my pocket. With the Pebble, I have the phone on "Do Not Disturb" at all times, and never miss any notification of importance. It's gotten to the point that the idea of having a device in your pocket broadcasting a loud noise to the entire surrounding seems like the stone age.. A little vibration on the wrist, and I know something happened. Then I can choose to take out my phone to react on it, or just postpone that.
I actually found that this increases the battery life on my phone (despite Bluetooth being turned on). Since I used to miss notifications (and would look at the time..), I would frequently take out my phone, unnecessarily lighting up the screen. No more!
So my idea of the perfect smartwatch is one that can provide decent notifications, and has a long battery life. I'd appreciate it if it looked good.. :)