Laptop hard drives tend to be more rugged than desktop hard drives simply because they're smaller. The strength of a material goes as the square of its dimensions, but its mass goes as the cube. So if you double the size of something, its strength increases by 4x, but its weight increases by 8x. So if you were to (say) drop the computer on the ground, the platters and read-write heads of the smaller drive would have an easier time resisting the forces.
The drawback is that laptop drives are slower. Many laptop drives are still 5400 RPM. And even if you have a 7200 RPM laptop drive, its outer circumference is only about 70% that of a desktop drive. So at the same level of technology (same areal density), a 7200 RPM laptop drive...