My experience with such manuals is, if you are already extremely familiar with the engine they are referencing in the manual, they are okay. There is nothing really Earth-Shattering in them that would seriously help you if never worked on such an engine before. They are written to cover too many engines with nothing particular on any of them. The original SHOP manual from the engine manufacturer is the absolute best, hands down.
Buy one for YOUR engine, model and year, and everything you ever wanted to know will be there with pictures as well. Yes they probably cost a few more dollars, but when you are in a bind, they pay for themselves over and over. JMHO