I recently renovated two bathrooms and bought the 18" towel bar frame along with a 12" tray and the 6" container for one bathroom. I bought them more for storage shelving than a towel bar. This set looks amazing! The tray/container has a glossy finish, which is what I wanted, and the bottoms are rubber with a rim around the edge so that it sits inside the towel bar frame. Be aware that on the bottom shelf, you cannot fit the trays/container the full width of the frame due to the vertical legs of the frame against the wall. On the top shelf, you can fit the full width. I like using the empty frame part to hang a hand towel.
As for the installation, it was very easy and quick but make sure to check the hole locations on the template with the actual frame. The width was a bit off on my template so I just marked the correct location on it and then had no problems.
Because this looks so great & is so useful, I bought another frame & trays for my other bathroom. I really love them!