The inertia pullers work, that's for sure, but be careful and ALWAYS wear eye protection. I had been using an RCBS puller until last Fall when I had part of the top of it break off and hit me in the right eye. Luckily I was wearing glasses so I suffered no major injury. The top screw on part split in two and half of it hit my glasses and right eyebrow hard enough to make me see stars. I heard a bang and saw a flash of light, then I sat there holding my eye, scared to move my hand and find out I was blinded. Ther glasses saved me. I actually thought something had detonated, the bang was so loud, but I was wrong. Evidently the bang was from when it hit my head.
I had used the puller many times, on concrete, and did nothing different this time, it just broke. I have another one, a Quinetics this time, and when I use it I look away on the down swing. And no, I don't swing it hard as I can, if anything I swing it too lightly and usually have to increase my down force a bit to get the bullet out, usually taking 4 or 5 swings in all.
After the incident my eyebrow was all swollen up for several days and really sore to the touch. Also my eye was weeping and sticky in the mornings when I woke up. My vision seemed to be OK though. Finally I broke down and had an eye doctor check it out, I was beginning to think I'd broken a bone around my eye socket or something. The doctor gave me a good report though and said it was just bruised. After a couple weeks everything was back to normal.
Just remember to use caution with the kinetic pullers.