thinking about switching attic vents, need some advice

Last summer, my attic got insanely hot and stuffy, even with a couple of box vents installed. A buddy of mine suggested ridge vents instead, said they made a huge difference at his place. I'm kinda skeptical though, you know, wondering if it's really worth the hassle and extra cost. Has anyone swapped out box vents for ridge vents and noticed a real improvement?