They're a lot cheaper but won't balance as well.
They will show the slightest bit of dirt.
They will never clean up properly past six months.
They are heavier, dragging down your efficiency of power and economy.
They are ugly.
Go with the aluminum. Spend the money and get it right.
Personally, I think the stock wheels look the best, but I'm a rarity.
Everyone has their opinions. I have never had any problems with steelies before and no one else that I have ever talked to about them does. I don't have the money to be able to afford to drop $1000 if not more on wheels and tires.
I do realize there is a price difference, but there is also a big weight difference. That weight wears out steering and suspension parts at an accelerated rate.
I spent $1300 just on my tires on my Jeep, then cheaped out with steel wheels. Now it's costing me even more because the wheels are causing balance issues (we tried the tires on different wheels to see if it was the tire or wheel) and now I'm going to be spending the money on new wheels anyway.
Whatever you choose, make sure it's what you really want and screw the rest. We're probably going to pick on you for one thing or another anyway.