I remember viewing a VTC Training Disc for Mac OS X 10.4, and the problem was, they used different teachers, and not all of them were good.
This one fellow, teaching the fundamental basics of OS X 10.4, to my amazement, started the tutorial with... crap like the BSD System and Core Services and a whole bunch of
highly technical under-the-hood type stuff, and I thought: Shit! What first time user or basic switcher is gonna understand this??
Don McAllister is a one-man show, and he's consistently excellent... ergo - stick with the teacher you like best.