Seeduino Stalker looks great, but it does not have USB connection. That is sad, as I do not have USB-serial adapter and I suppose it cost as much as I would save... I assume that I need to convert serial to USB.
I have read that Xbee is almost plug-and-play. How does Synapse compare to this? What about having several slave transmitters and one master. I know that with Xbee that should be possible but don't know about Synapse.