Hi,
One thing to remember about manuals is they fall into the same category as most everything else "reloading related": there are many ways to skin the cat, and folks develop their preferences for a variety of reasons, most being ok to good.
My preferences are often based on what I need at the moment:
Lyman (several versions, such as handgun, shotgun, cast bullet): good mix of data w/ a variety of components, lots of great "how to" info. They do their own testing so you're getting "yes, we tested it" data, w/ pressures, velocities, and other vital info. Advertises Lyman products w/o being too hard sell about 'em.
Lee: a fair amount of good "how to" info, 'specially for the guy just starting out. Some interesting opionions--Mr. Lee was not bashful about sharing them when he started writing. Lots of load data in one place, but it's all compiled from other sources (normally the powder mfrs' booklets) into somewhat generic recipes. "Start low, work up" is especially important to remember when reading this kind of data. Tries to sell you Lee products.
Sierra, Speer, Hornady: all have plenty of good "how to" info w/ lots of data on load recipes. They do their own testing. I'm careful about using Speer data w/o double checking it against other sources. They HAVE put some pretty hot stuff in one or two of their books in the past, and still don't share my thoughts on "a good recipe includes pressure data." All try to sell you their bullets. Hornady will have their presses in the pictures; Speer will have RCBS (they've been associated under the same umbrella over the years) for a bit of extra advertisement value. You may notice other brand preferences in their data for the same reason.
Powder mfrs' booklets: available in print and online. Good source of thoroughly tested data, probably derived under the best lab conditions, but there are still enough variations in testing protocols that you'll find variations from the powder mfr and the bullet mfr if you compare otherwise identical loads from the two sources. All try to sell you their powders. Again you may see certain brand preferences in components because of various business alliances (for example, Winchester makes all the components for a loaded round, so their data uses Winchester components most often. Alliant furnishes a lot of powder to Federal, so you'll see a lot of Federal brass and primers listed. Speer, RCBS and CCI all share that umbrella mentioned above. And so forth...)
So...
There's no "perfect" book. Building the most extensive library you can is a wise idea. Mine's not as extensive as I'd like it to be, but it grows. It's not hard to collect a couple of dozen books or more, 'specially if you update them when new editions are printed (ALWAYS a wise choice!)
Rick C