I own mostly steel tanks. Properly cared for they will last a lifetime! Less weight on my weight belt. For a small or short person they are more compact than an aluminum and easier to handle. For a tall or large person they may not trim out as well in the water. Unless they wear the tank very low then it is hard to reach the valve in an emergency on a 80cf steel not a problem with a 100 or 120cf steel for example. Depends on the diver and there setup. Getting a short fill depends on where you go. Many places fill them properly also are we talking about high presure tanks? They are made with different presure ratings. Aluminum 80 are popular because they are cheaper saving dive ops in alot of capital out. Easier to sell to most divers because of there affordable. And just a good all around for average divers. Comercial tec and cave mostly use steel tanks except for pony deco and stage bottles. But that can vary.