When you just absolutely need to have your Facebook & Twitter feed ASAP and taking out your phone from your pocket wastes too much time... This is the SmartWatch by Sony (Ericsson). SonyEricsson had 3 versions before this one. The first 2 versions were regular analog watches with small displays at the bottom that indicated incoming calls or texts. The 3rd generation, LiveView, had a color display and touch sensitive buttons (not a touchscreen).
The new incarnation is a bit more mature, and packs more features in a tiny display. In it's basic watch mode, it offers 3 time-keeping modes, Default Digital, Always-on Digital, and Always-on Analog. My preferred mode is the analog. I just feel it looks sleeker than the digital counterparts, but that's just me. Although the default version saves a lot of battery life, I'm not too fond of the look. You may download alternate clocks, but none of them replace the built-in ones, so they actually are apps that run parallel to the default clock. Until Sony allows addition clock replacements, I'll stick with their built-in ones for now. Battery life in this mode is approx 1.5 days.
Now onto the apps. Out of the box, nothing comes preinstalled, you have to first pair your phone with the watch. Quite an easy task. Just enter your Bluetooth settings on your Xperia phone, and search for a new device. Turn on the watch and the pairing automatically begins. To activate the watch however, your phone must be online as it will connect with the Google Play servers to update the watch software and search for compatible apps.
There are currently only a few apps out for the SmartWatch but it seems to be growing quite quickly for such a niche device. The essentials are provided for by Sony, mainly: Gmail, Calls, Calendar, Messages, Facebook, Twitter, & Weather. The other apps available are extensions for Google Maps, Universal IMs, Camera apps, and a few GPS ones.
I ended up installing so many apps, that the watch kept buzzing for every single thing I had on my phone. Trimming down to the most frequently needed alerts improves the effectivity of the SmartWatch all together. I've personally got mine down to just calls, SMS, only calendar events with reminders, and only a few people on Facebook. Everything else isn't as time-critical.