IMO, a bow is harder to use than fire pistons. Bows can be a workout.

A hand-drill is harder to use than fire piston. Fire pistons are kind of hard on your hands from slamming the piston, but no where near as hard as a hand drill is on your hands. Drills can be a workout too.

Flint and Steel is more reliable than a fire piston. I would say they are easier too. With good technique, it takes seconds to create and catch a spark. If your fire piston is in working order, it is pretty quick too. Both work best when you have good char or the like to catch the spark (flint & steel) or create and ember (fire piston)

But fire pistons are by far the most interesting to me. I have made several.