My situation is greatly different from most of the above, but the reasoning still applies - the BP/W center of gravity.
I should not carry any weight on my back / shoulders. In the BC, I could not trim horizonal without putting four pounds in the upper trim pockets, four more pounds in the BC weight pockets, and the rest on my hips in a weight belt (I dive 5mm and up wetsuits).
So, not only was I wearing an 8.3 lb BCD, but adding 8 lbs to be carried on my back. The out-of-water weight is my biggest concern.
After reading many opinions and testimonies on this board, I bought a BP/W with SS plate. Total weight - 8.2 lbs. A push, in my opinion.
Trying it out in the pool, I found out my Tusa fins were floaty . . . because the BPW did not need weight to trim it out, and all my weight was on my hips . . . exactly what I needed.
I had to get new fins, but I was not carrying any extra weight on my back.