My personal opinion is that if you're shooting an absolute TON, it might be worth it for the cost savings. But steel is really dirty so you gotta clean out your barrel after you shoot it (in theory, we all should clean our guns every time we get back from the range, but in practice, if everyone was honest, we don't). So if the cost savings of shooting steel casings is greater than the time expense of cleaning your gun every time, then go for it. But if it isn't worth it to you, then just stick with brass. Here's a really good break down on it.