The real deciding factor is how much you shoot it/how much you carry it.
Shoot it often, go with steel. So much more pleasant.
If you carry it daily and shoot it infrequently, you will appreciate the alloy.
If you want to compare the weight you are carrying, don't forget to factor in a loaded magazine. The relative difference when you do that is not that dramatic on the hip; it looks more dramatic on paper when compare empty weights.
A better way to look at it is, how many quarters are you carrying with a loaded alloy vs. a loaded Combat? I'm not trying to tell you one is better, but to think of it in the big picture.