It's tough to beat a good seasoned brushpile as long as it is fairly open so that the larger crappie can get in and around the limbs. Also I've noticed if they come off the bottom 4 to 5 feet at least,they seem to hold fish better than one that has settled down tight to the bottom.
I have built about every type of structure that I have read about and caught fish on them but it's still hard to beat some of my best brushpiles!