I currently have a Buzz xpl3000 which I subscribe to two services,I have the two set up as mac address,I am getting a new Buzz xrs-4500 next week and I dont believe you can change the mac address on the new box.What is the difference between setting up with mac address or user pass? I have talked with one of my providers and he said to send new mac address and he said he would switch it over but cant change to user pass.Is there an advantage between user pass and mac address? Thanks.