Planks come in several widths, thicknesses, and colors. If put together and installed correctly, they last a right smart time. If there is any kind of impact, they have some give, but when they stop giving, they splinter, then they're like broken glass and very dangerous. They are great for geldings and quiet mares, but are not sturdy enough for stallions. Horses usually won't chew on it, and it's very strong.
Cost is fairly expensive.
The bands are highly visible, somewhat resembling narrow, white-painted board. It's designed specifically for horses. It has an elastic quality, so if the horse hits it, he'll bounce off, or if he sticks his foot through, it won't cut him. Of moderate price, coated wire is long-lived and maintenance free, usually requiring annual ratcheting to keep it tight. The exposed wire at the end should be bent and tucked around or covered with a guard.