[Sony Smartwatch 2] Linuxslate:
... Lasted about 3 months.

I was washing something in the sink with my SW2 on. I used a small amount of common household cleaner containing a bleach.

A few hours later, my watch was blank, and would not turn on. It would also not charge (As indicated by a USB test meter that showed little or no current when the watch was connected.)

I took it apart, and here are the results:

There is a rubber cover at the top left of the device (seen after removing the watch module from the plastic frame). This cover was mostly deteriorated. Likely from previous wear/sweat/washing, not this episode. I am not sure what the rubber cover is, but I guess there is a sensor there (pressure sensor?)

There is no seal on the plastic frame. Water/chemicals/sweat/dirt that gets between the frame and the watch module will stay against the rubber part.

The watch always fit poorly in the frame. It was very easy to remove.

Water, possibly containing dilute bleach entered either from either the deteriorated rubber cover, or the USB port (The USB port cover was properly closed, although it is not particularly soft, and not a material that is likely to form a good seal.)

The a small amount of water seems to have accumulated in the corner of the PC board, near a small square chip that I assume is power management. Some SMT discrete components in that area were affected by the water/chemicals, and were totally oxidized or gone.

Conclusion:

Obviously, I should have removed my watch before using the cleaner.

Simply press-fitting the watch into the plastic frame is not an adequate way to make something like this. Even US$20 Casio watches are built better than this.

The device is not adequately waterproof. A better seal for the USB port should have been used. Even better would be to use a waterproof charging system. Sony already has their magnetic charging port, which is waterproof and un-covered on my Sony Xperia Z2. Why they did not use this port on the SW2, I have no idea.

The SW2 is definitely not up to the build quality I expect from Sony.

Replacement:

The watch seems un-harmed except for the damage to the main board. Very little water (less than a drop) entered the watch. It would be very easily to replace the main board if I ever find one. I am sure there are plenty of SW2's out there with cracked screens, and perfectly good MB's. Perhaps I will find one at a good price.

I certainly do not plan to buy a new SW2 or a SW3. IMHO, the Sony Smart Watch 3 does not provide any compelling advantage over the Android Wear competition.

For the near term, I intend to buy a cheap Smart Band such as the Vidonn X6: http://vidonnx6.com/

I am waiting to see availability and prices of the Huawei Smart Watch. http://consumer.huawei.com/minisite/worldwide/huawei-watch/

I really like the look and features of this Android Wear device, and I actually trust that Huawei's build quality will be better than Sony's. I was very happy with my Huawei Honor 2. It still works fine, and still looks pretty good too. If it had NFC, I would probably still be using it as my main phone.

If either the Huawei is too expensive/never released/etc., or I find a black metal band Moto 360 at a good price, I'll get the Moto 360.

Sorry, and Good-Bye. I really like the features and battery life of the SW2. I wish I still had mine, which is to say that I wish the build quality had been better. I really wish I could have stayed with Sony for my wearable.