I had them on my first road bike, and since then on several old bikes I picked up from friends or the trash. I found the safety levers useful and not dangerous in any way, but I almost never rode or used them from the top of the bar. I liked holding the bar at the curves just behind where the lever is mounted.* Here, my fingers can comfortably and securely operate the safety lever nearer to it's pivot.

It worked well for me but I also always kept my braking system and entire bike in top condition... which you should be doing no matter what system you have!

*Palms facing towards each other, similar to holding the hoods.