This debate will go on forever and with good cause.
Personally I prefer not to use steel cased ammo in my firearms, I am meticulous about the care of my guns and prefer to use only quality brass cased ammo in them.
Here is a link to an article on LuckyGunner.com that does an excellent job of testing both brass and steel cased ammo in identical firearms and comparing the results.
This is a long read with tons of data that may end the debate in your own mind. It has reinforced my reasons for choosing the ammo I do.
http://www.luckygunner.com/labs/brass-vs-steel-cased-ammo/
