We are hanging our wood shelves that are going to go around the entire room. What would be the best support?

We made the shelves to be very long and will be holding quite a bit of weight. Originally, our brace was having another piece of wood underneath it the entire way around it. However, we have been seeing a lot of the shelves put up using the triangular brackets/braces that are placed every couple feet. Which one do you think would have the most support???? Please help! We have been debating on what to do. Thanks in advance!