Here’s a good article we wanted to pass along. It deals with the pros and cons of both steel and copper plumbing pipes.

Steel can last for a long time but its harder to work with than copper and over time there is a chance of having small quantities of lead come out of the metal and into the water. Copper fittings are also durable but they are more expensive and are more likely to split when the water inside becomes frozen.

Here is a link to the full article with more details.
Steel vs Copper Plumbing Pipe Fittings: Pros and Cons