All electric apartment vs Gas/ Electric: which one is better?

I have heard all sorts of stuff.. mainly I want to know how much of a difference in money it would be. I live in an all electric apartment but will be moving to one that is gas/ electric. Right now I pay on average around $50's per month. Roughly (as I know, certain aspects affect this), how much of an increase would I see? Also, if you have any good energy conserving tips, they would be welcome too.