In my experience only. Advantages: Probably for warmer climates very few SHB if an oil, or water pan is used. Diatomaceous Earth has been successful for some but it cakes to quickly for my area. I build my DSBB with 2 3/4 inches between screens, which allows a casserole pan with about 3/4 inch of oil in i to be inserted from the rear of the hive. Before moving a hive I strain the used cooking oil and reuse it. Messy, yes, but fore thought can make this a non issue . I see absolutely no bearding on hives all deeps up to 4 high in the Texas sun. I use a door on the rear that is bee proof which allows me to change oil without the bees ever knowing I am there. If you like a landing board the DSBB makes this easy to incorporate in the construction. I also use the idea of Jim's that is a screened top board with a cloth and sawdust or shavings year round. I have no mold in the winter. There are Master Bee Keepers, I am NOT a MB, that leave the DSBB open all year, I have done this also with no bad results I just like to make sure all my girls are snug and comfy. My major disadvantages Time and cost to build, weight and some added bulk, especially if hives are moved. I wish I had numbers to prove that DSBB improves mite control, all I can honestly say is that it has to help. I strap all my hives which helps make them tighter, also cows and horses love to rub on hives and knock them over. I have LOTS of hogs but they have never been any kind of a problem for my bees. I first used SSBB and the bees started comb on the bottom of the screen. Summary; Dsbb will work for you if you want it to work but they won't if you don't want to use them or have a preconceived negative opinion. Its just another tool.