Sword and Shield is the most basic weapon type, being easy to learn and use. When you create a new character, you will automatically be equipped with this weapon type.
SnS is fast, but not blindingly so. It has a shield, but it's only a small one. Essentially, it's a balanced weapon, without much focus on any particular play style, and a good choice when first starting out.
It should be noted that SnS weapons tend to have very low raw attack power. Instead, most of them have elemental damage as well.
Recommended for noobs.