Hard weights are smaller than the same weight soft weight. If your weight pockets interfere with the storage pockets when very full, then hard weights are preferred.
Soft weights are slow to dry and leach out small amounts of lead. In other words, hard weights, particularly those that are plastic coated are more envirionmentally friendly.
Hard weights are rougher on the weight pockets. After about 300 dives, mostly with hard weights, there are some wear points from the corners of the hard weights on the pockets of one my BCDs. On a practical basis, this isn't all that important because the velcro is getting weak by the time this wear is an issue.
Soft weights don't move around inside the weight pocket as much as do hard weights. When putting 4 pounds of hard weight in a pocket, I'll use two 2 pound weights rather than a single 4# weight whenever possible so that they stack up against each other and won't move around as I do backrolls or other underwater acrobatics.
I bought soft weights for my BCD, but have gone back to using hard weights.
Don't sweat it. Either soft or hard weights will work in your weight integrated BCD.
Charlie Allen
