Dacor RIG BC. When I began diving I used a hard pack and wing. When I began diving doubles a few years later I thought the RIG would be perfect. The weight of my doubles ripped the back of the BC out. I repaired it with grommets, but a few dives later it ripped again. I've gone full circle and have used a backplate and wing for the past few years now.
My only other regret was spending $1800 for a DUI TLS350 drysuit. After nearly 200 dives in the suit, I remained dry on only about a dozen dives. It went back to DUI twice with no luck. They couldn't find any leaks. I ran my backup light along the inside and found several pinholes. I patched them, sold the suit on Ebay and bought a Diving Concepts suit for $230. Until I recently tore the neck seal, I remained dry on every dive.