Casement windows open wider than other types, so they can funnel lots of air through your home. They also insulate better, because winds push the sash more tightly against the seals. To get the screens out of the way, you usually need to pull them out.
In windows with cranks, the crank can fail. This is the biggest maintenance issue. Keeping the gears clean helps.
Lifespan: 15-20 years