This is a great article on how to make the choice when deciding on a rework station. Hot Air VS IR covers some background information on the 2 main types of rework stations on the market. Either using Hot Air which is older technology or using newer IR with the Dark IR spectrum that utilizes convection and radiation to heat. There are few options when trying to choose BGA rework machines, its not as if you can TEST DRIVE them. So do the research and get the best station for you.