I personally use them, as an extension of your smartphone. Sony writes that operates the clock with virtually all smart phones (with Android 4+) and I can confirm that.
Connecting the clock via NFC is simple. Those without NFC can it easily with BT. Both devices consume surprisingly little battery power. Despite connection via BT can be parallel or hear music phone with a headset / car radio via BT.
Unlike Sam ..... Gear you can make phone calls or any photos. OK, but the connection technique as already mentioned, it is possible that the one or other app deal. Take pictures with the phone, triggered by the clock or answering calls, reject, choose and much more. is no problem.
It would also be possible to write SMS, but that really is nonsensical, because the display of this is really too small.
I guess that there are around 200 apps alone for this SW2.
The first application of the clock:
Processing I find successful and splash is not a problem. Water I myself will not be run over even if the clock that can have from.
I adjust the clock very well and is really easy. The bracelet feels pleasant, but has the disadvantage that lint etc easily remain hang.
Clear + Are there any that you can change the tape. Other manufacturers, known especially can not because of the built-in technology.
The battery has maintained for 3 days with me, although I've already used phone calls, Facebook, Instagram and What's App. I think, the 4 days are available and that this is also ok. In the future other models will create more, but we indeed live in the present and if you are honest, some smart phones provide not even 24h. ;)
Finally, I can recommend all the person you would the clock, the technology are enthusiastic. Want to retrieve important information without into their pockets and those like watches.
There will be future better watch, but the same is also the case with smartphones.
Hope I could help in the purchase decision.