I have both natural and artificial cover. The advantage of artificial (porcupines) is that they are easy to assemble, place, move, and generally don't steal your lures as often, etc. I generally place artificial structure close to cedars and hardwoods. I placed several cedars over 10 years ago, and although most of the limbs are long gone, the remaining limbs and trunks still hold fish. As far as cover having the ability to attract and hold cover I am convinced that natural is generally better.
It is amazing how some of the natural cover remains for years. My pond was built in 1954 and when I lower the lake level several large stumps are still intact and holding fish. There is a 30 inch tree stump that is cut off about four feet under water close to my dock. Until I lowered the pond more than four feet I didn't even know it was there, I just knew I consistently caught fish in that area.
