Depends on what you're going to do with them. Series like Men at Arms, Warrior, Elite, Aircraft Aces, etc provide a few good color illustrations and a decent amount of supporting information that I suspect are very useful to modelers, gamers and visual arts folks. As history references they're a bit spotty. Some of the information, especially in the older titles is not always on target. I like them for the same reason I enjoyed Playboy - for the pics! The pics are great inspiration, take some of the text with a grain of salt.
I have not read this particular Doolittle title - it's a title under their Campaign series:
Doolittle should probably make for a good enough read in 100 pages or less. It's a more or less a slowly progressing linear engagement where a lot of things aren't happening all at once.
WmB