Music-Minus-One recordings. The problem with BIAB is you're learning nothing about interacting with other musicians and nothing about how humans play music. Music-Minus-One recordings are not only real players but masters of the art. BIAB is appealing in its convenience but when you slow down to a realistic speed with which to absorb a tune (very slowly) BIAB looses that appeal and starts to sound like the mechanical contrivance it is.
