drag blocks?

can anybody give their opinions on drag blocks. do they work, how long do they last, anything besides them that throws sparks? ect

FORGET ABOUT THE BLOCKS.JUST DRAG IT. I DON'T THINK TWICE I'LL DRAG DOOR ANYWHERE..

i here all these people saying that hitch balls can break easy and go flying threw someones windshield. looks like a big enough bolt to me but, has anyone ever had that happen?

I use some drag blocks that I made, there's a pic in my profile. They are made of steel, and at the rate I drag through them, if they weren't there, the bottom of my frame would be gone in a couple of weeks. I personally don't have the time or energy to re-plate my frame that often, so that's why I use blocks. Here's a quick draggin video just because (my truck's in the middle lane) Click here for Video