I've done it a few times and I expect I'll do it again. I wouldn't recommend doing it to 'flip' cars for a profit. In some cases you can find a gem. In most cases, the parts and labor to do a
quality job will put you near the cost of an unblemished one. If you want the car for yourself and enjoy the challenge, I highly recommend it as a recreational drug. Just don't bet your grocery money on it.