Here is what I do: When I dive in Monterey (about 50 degrees F) I use a 2 piece 7 mm wetsuit, so I use about 30 lbs. I have 10 lbs on a separate weight belt, and the remainder in the BC. I have 5 lbs on each side in the rear in non-dumpable pouches. I also have about 5 lbs in each of the integrated pouches that are dumpable. I have a ScubaPro Glide Plus.
This set up gives me the following advantages (in my mind).
1) I can dump 5 or 10 or 15 or 20 lbs in stages.
2) I can adjust the trim by where I place the weights.
3) Most any other diver could figure out how to release my weight belt in an emergency; I don't have to rely on them figuring out my BC quick release pouches in a panic situation.
4) If I accidentally release one of the integrated pouches I ride a much slower elevator to the surface.
5) The integrated pouches fit easily into the BC, even when I am wearing it.
When I first started using the Integrated weight BC it was a little tough to fit all the weight into the pouches, and it was awkward to insert the pouches into the BC, plus it made a real big lump in the BC. Now it is a lot more streamlined.
When I dive warm, I use a thinner wetsuit, and a lot less weight, so no weight belt. It all works out very well for me.
***************************
My buddy is even more bouyant than I am, and he uses about 40 lbs when he dives cold in his 7mm Two-piece Henderson Gold Core. He had problems with getting all the weight into the BC pouches, (first with an Oceanic Chute II and later with a Zeagle Ranger) and he had a LOT of trouble getting the pouches into the BC. There was no way that he could put the pouches in while he was wearing the BC. He has no hips, so a weight belt was not a good option for him. He bought a DUI weight trim harness and he loves it. He keeps some dumpable weight in the DUI and the remainder spread around his BC, some dumpable, some non-dumpable. Now he can carry the Ranger weight pouches and install them into the BC at the rear of the boat, and basically everything works better for him with this set up.
When we were in Florida, he used a 1 mm Henderson and he used a lot less weight, so no DUI, just weights in the BC.
======================
Keep the old weight belt arond, you never know when you might be able to "save" someone by having something they need.
Just my two cents, and my buddy's,
Wristshot