I bought the largely similar books on mechanical components by Sclater and Parmley. Both have drawings of similar quality, to the point of having identical drawings in a number of cases (presumably because both authors used the same third-party source for the particular topic). A very few drawings were disappointing, but most were very good indeed -- and even the disappointing drawings probably would be fine for most engineers (I am not one).
There are differences. The Parmley book presents more examples of certain devices (for example, more types of linkages). But that is not true for all devices, and I'm not sure it matters in the end since both books offer quite a variety of most. For me, not being an engineer but being a fairly quick study if I'm presented with something to study, the Sclater book was preferable because it included, in most cases, more detailed introductory essays about the variouse sections: gears, screws, linkages, solenoids, etc. In some cases, though rarely, Parmley's explanations were skimpy.
I'm trying here to draw some helpful distinctions, and hope I have, but I'll close by saying that I think both are great. If I had to choose, Sclater's would win, but if you can do without the more detailed explanations and would prefer marginally more devices presented, Parmley's may suit you better.