I agree that the American Angus Association (AAA) will have lots of good information, but remember their job is to promote the sale of Angus cattle not to tell you whats wrong with them.
The biggest fault I have with the AAA is that they tend to promote that their cattle can be almost all things to almost all people. For example, they promote the use of purebred Angus bulls on purebred Angus cows, even in commercial operations. They seem to ignore all the research on crossbreeding that highlights hybrid vigor, increased cow efficiency, etc. The AAA does more promotion of maintaining purebred cattle in commercial operations than any other breed I can think of. It is kinda nice to see many breed associations (including Gelbvieh, Limousin, Simmental, Hereford,Red Angus,...) actually promoting the fact that commercial producers should do selective crossbreeding to improve their bottom lines.
I think Angus cattle (both reds and blacks)do a lot of things right. But they have some shortcomings, including
-The majority of purebred Angus carcasses are too fat and don't yield enough for most packers
-Angus cattle in general have a poorer disposition than the average Hereford, Shorthorn, Gelbvieh, Simmental, and several other breeds.
Just some of my thoughts. Good luck.