Both are great if they are the right thickness and installed properly.

Kt

If using plastic, it needs to be real bamboo barrier, which is a special, high density product. You do not want to use something like a kiddie pool because the plastic is weak for this purpose, it has no drainage, and the rhizomes will go through the bottom if you put holes in for drainage because it is not deep enough. Below is a link with some helpful info on barriers.

Here is a link that might be useful: Controlling bamboo