I breed neither Angus nor Charolais. Both can produce excellent beef, and frankly how the cattle are handled, finished and the meat is aged can have a major impact on the eating experience. Now what I'm going to say is generalities, and what experience has taught me, it is NOT gospel...
Charolais, in general, have less intramuscular fat, which can lead to the meat being less moist and flavourful. Angus have more--unfortunately sometimes so much that you're trimming half your steak to avoid large chunks of it. If you want lean burger, charolais is much better, because most fat is laid on the surface and is easily trimmed pre-cooking. If you want a large roast, charolais are likely better. For tender, frankly I pick a different breed altogether.
The angus breeders have CAB, which is a good marketing tool, although other breeds (with a black hide) qualify for their program, thus it really isn't "certified angus beef"--and red angus don't qualify at all....
My preference, frankly, is neither of the above to eat. But then, that's just me!
Hope you find the answer you're looking for!
V