I have several of the firearm-specific videos and in general I like them. They do a fine job of explaining and showing how to disassemble and reassemble the entire firearm. They cover common repairs and how to inspect for parts that are worn or damaged. Lubrication and maintenance are typically covered.
On the tapes I have seen, the gunsmith is very knowledgable, and has a wealth of experience to share. The videos are not glitzy or slick, but give some very practical info for the home gunsmith or gun owner wanting detailed knowledge of his or her firearm.