Opinions are what you asked for and what you will get. Since you asked, my opinion is it depends on your experience and knowledge of how stuff works. For the most part, the factory ones are written for the guy in the dealer's service shop, and assumes he knows which end of the screwdriver fits the slot. Seloc does a better job of explaining the elementary stuff, but is notorious for errors, and covers too many models to do a good job on ALL of them.