Although the pieces that hold the shelves up are plastic you cant really tell once they are up on the wall. I was worried that they would not hold heavy stuff, but each shelf is separate from the others although you can put them together. I have heavy glass pieces on each shelf and they are sturdy. Would recommend using larger screws than the ones that come with the unit for heavier items. 

Pros: Gives a lonely corner great charm to display all your favorite collectibles.
Cons: Non really except the time to put them together.