Basically you are lowering the entire camber link, which I believe changes the camber change arc.

I was having this discussion with one of the local team drivers. The impression that I get is that one is not better than the other. They are different. I'm going to try the A hub and C hub on my next practice day and see if I can pin down exactly how it makes the car feel different.

Just remember as Tyler stated you need to shave the U Hub brace if you run the C Hub. After you shave the hub, if you want to run the A Tower, remember to put 2 washers under the inner ball stud (or just have 2 U braces made up, one stock, 1 shaved.)