Personally, for flat surfaces like tank and sump walls, I still prefer bulkheads. For surfaces that are somewhat flexible or aren't flat, like garbage cans that hold freshwater or salt water for water changes, I prefer Uniseals. I just worry that I'll crack my tank (glass or plexi) when I try to push the PVC through the Uniseal. Even when I used them on my garbage cans, I found myself spinning and twisting the PVC to get it through the Uniseal. I can't imagine doing that on a tank.