bamboo will not only spread throughout Florida, but will spread the whole way to Maine, if given a chance :-)

Holly or something like it will block a lot of light. Living in Florida, you have many options for large clumping bamboo which, by definition, will not run and will give privacy while not blocking light as much as another type of hedge.

American Holly seeds are all viable, even 20 years after the tree is gone. I hate pulling holly seedlings out of my flower beds!

Wait wait...bamboo fencing, not living bamboo, right? (Personally I'm a fan of clumpers, though).

fori-
The OP's post is a little confusing. I assumed that the question was about a tall, growing privacy fence. Since bamboo fencing is usually about 6' tall or less, I thought the post was about live holly vs. live bamboo (and I'm not sure what "composite" has to do with it, unless that means a combination of the two.)

OP: can you clarify?

The fence I am considering in terms of bamboo is the decorative prefabricated one not a live bamboo trees. I did wonder about the seeds from american holly whether they spread throughout the yard. In terms of composite fencing, I am talking about the vinyl etc. I just need some advice from people who actually have these kind of fences in terms of maintenance, cost, height etc. I do appreciate everyone's opinions.