From Amazon. Setting it up was easy; just downloaded the relevant app to my Xperia Z3 Compact (it will work with any android device with 4.4.4.) and started adding apps - it accepts a maximum of 9 apps on the band, plus it has Sony's excellent tracking abilities and syncs with the Lifelog application. You don't need the phone with you just for tracking exercise.
Call quality is good - both receiving and making calls, the loudspeaker is of good quality and pretty loud.
What I like most is that the band looks elegant and nicely fits my wrist. I didn't want a Pebble or any of the current android wear devices. The display is reversible and you can change the text direction depending on whether you wear the band on your left or right wrist.
All the normal smartphone notifications are displayed, and you can adjust these through the app. Some shots of the app itself:
