There are 4 main material options for steep-slope roofs: shingles, slate, clay tile, and metal.
The most commonly used material is shingles, which has an average useful life of 20 years. Shingles can come in traditional asphalt form, as well as in rubber or steel.
Slate and clay tile, while beautiful, are the most expensive of the options and may also require expensive maintenance. Because slate and clay tile are natural products, they do not come with a warranty. This lack of warranty can cause extensive repair costs, especially when considering that problems caused by improper installation can start soon after the installation. Further, slate and clay tile roofs can only be attached to a roof by mechanically attaching them, which risks cracking the slate or tile, or clipping them, which may allow for water to seep underneath, freeze, and cause the slate or clay tiles to become detached from the clips.
The third option is a metal roof. While it is expensive, it is relatively maintenance free and gives a modern look that many desire. Metal roofs are installed with clips and proper installation is important to ensure that water seepage does not occur. Schmidt Associates typically specifies two roofs to avoid this problem; a rubber membrane under the metal roof. Hail can also create problems for metal roofs. Damage from a hail storm can be significant since the metal can show dents just like a car. That damage, however, is usually just aesthetic and the metal roof can continue to perform leak free. Without hail and with proper installation, metal roofs can last up to 20 or more years.
Here is another post about roof material options for low-slope roofs, as well as which option we prefer and why.