I was very excited about this little gadget and thought that the Sony Ericsson brand and the cost of the device assured me of its quality. However I am actually very disappointed in it.
Firstly the screen, although AMOLED, really is quite poor. The resolution is low and the colours are all washed out. The strap that comes with it is a bit crude and when worn as a watch looks very unstylish.
Next and most importantly, connection; I succesfully connected to my HTC Desire HD but it loses this connection - a lot - and it's not because I am too far away either. I can't stress how the process of reconnection is extremely frustrating and takes a lot of attempts. It defeats the entire purpose of this device. Now I know there have been issues with BT connectivity on the DHD but I see other makes and models having similar problems with this gadget. (Samsung Galaxy S, Desire, Wildfire)
As for transferring of data, that seems to be fine once connected, but don't expect all features to work with non Ericsson phones. I could not use media player function and calendar reminder for example.
The user interface is a bit fiddly too and one feature to 'remote control' your phone to show the full version of an article you have on the LiveView, is hit and miss too.
Now obviously this is a new device with a lot of potential from developers to introduce their own plug-ins, and software updates may eradicate some of these problems. But for now, I feel that it's too buggy to be useful and you are best waiting for it to be more established. It may be fine with SE phones but as it clearly states it is compatible with all Android v2+ phones, so I expect more reliability.