Chevy Duty (Now Classic Parts) is great for some things, LMC is great for others, Brothers has always been overpriced for the same items. There are others to consider also such as American Classic, Truck Shop, Jim Carter, Yogi's, Chevy of the 40's, and others.
Look for the best price since the products all come from the same basic suppliers. These outfits are just resellers/retailers.
I have never had a bad experience with any of them that did not get resolved to my satisfaction.