I have been informed by an employee of Sony Ericsson USA that the LiveView was not released in the USA, and any you can purchase here are "grey market" items that they will not support.
I cannot in good conscious recommend that anyone in the US buy a Sony LiveView under those conditions.
Further, it took five calls to their tech support line trying to get support for this device before any of their tech support staff noticed that this was a device they didn't support. The skill and training disyed by Sony Ericsson's tech support staff during those five calls leaves me unsurprised by this.
With tech support of that quality, I have no choice but to recommend avoiding any product sold by Sony Ericsson USA, no matter how tempting it may otherwise be.