Charolais & Angus are a terrific cross! I know from my own experience, switching from straight angus to a char/angus cross, that I gained 100 lbs. of weaning weight per calf. Bull selection, as with any breed, is a critical factor. When I choose Char bulls, either for my white heifers or black cows, they have to meet 3 basic criteria; calving ease (70# to 75# birth weight), sound functional structure, and good disposition. I realize I'm probably giving up some weaning weight with smaller birth weights, but I feel I realize more with unassisted births, live calves, and cows that breed back faster; all benefits of smaller birth weights. I've pulled fewer calves out of char bulls than I did the angus of hereford bulls I used previous.
A downside maybe if your going to maintain your Angus cow herd you will have to buy replacements. This is entirely up to you, I've saved many of the first cross heifers and they have made excellent cows.
In the end do what is best for you & yours and your entire operation...as much as I like the char breed, don't chase any trends in cattle or any one aspect of any breed. Well rounded (no pun intended :wink: ) cattle, regardless of color, with good management should work well for you.
Here's a link to some pictures of my calves I posted this fall.
http://ranchers.net/forum/viewtopic.php?t=40516&postdays=0&postorder=asc&start=0
All the Best