So I got my vuvuzela in the mail today. I ended up playing it the entire WC match, and it just made the experience even better.
A lot of people seem to think that there is a reed or other noise maker in the horn. However, the (in)famous sound is made by buzzing your lips. This horn is not missing any parts. As mentioned in the description, the horn comes in two parts. Mine came pre-assembled, so all I had to do was extend the inner piece. I actually prefer the horn in two pieces, so that it is easier to transport. As far as I can tell, this does not hinder the sound. Oh, and the plastic is sturdy enough for me.
I am glad I made the purchase, and I look forward to being "that vuvuzela guy" at every sporting event I go to from now on.