Both are too easy to hurt yourself. This is why, for example, why deadlifts are generally not recommended for professional athletes. For example, notice Kobe doesn't do deadlifts: http://www.nbaplayerworkouts.com/kobe-bryant

The delta in benefit is not worth a back injury.

That article says Kobe does power cleans, which are riskier than deadlifts for back injury.

I tend to find them a lot safer. The weight used is a lot less and is much more forgiving of improper back posture. With that said, for beginners, I do think that the Power Clean is more dangerous. More places to make a mistake. But for an ahlete with strength training background, deadlift is more dangerous, I think largely due to the weight. I've seen too many people with what looked like perfect form hurt their back.

I have a back injury from weightlifting in high school, so I view deads (and the entire "olympic lifts for desk jockeys" meme) with suspicion. However, I think people mainly get in trouble because they try to do too much weight, too soon.