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Thanks for asking.
You can find a list of compatible receivers at
http://www.iospirit.com/products/remotebuddy/hardware/
Remote Buddy currently supports Tiger, Leopard and Snow Leopard.
Please keep in mind that the USB standard defines a maximum length for cables. According to http://www.usb.org/about/faq/ans5
-- excerpt --
Q1: How long of a cable can I use to connect my device?
A1: In practice, the USB specification limits the length of a cable between full speed devices to 5 meters (a little under 16 feet 5 inches). For a low speed device the limit is 3 meters (9 feet 10 inches).
-- / excerpt --
In contrast to USB, Bluetooth - under optimal conditions and depending on which power class the participating devices belong to - can bridge 1 meter, 10 meters or 100 meters (=> http://en.wikipedia.org/wiki/Bluetooth).
Best regards,
Felix Schwarz