they don't really teach you much more than if you went to a lesson and asked a few questions of a teacher?
the metal bass one I had was just using pedal notes, hammer on and pull offs, what the role of a bass player is and using fingers or pick,...
the doug whimbish one is interesting cos he teaches you alot of 'different' outside the square sorts of ways to play your bass,... still wasn't as in depth as I thought it would be / would like it to be
