On going to install this item, I realised that two screws at the top would not be enough to stop it moving around (which is mentioned in some of the other reviews). I put in two addition screws near the bottom which solved the problem. However, I'm not sure why the unit was designed with only two screws when clearly four are required!
Secondly, when positioning the item in the shower, I noticed that the whole metal frame was slightly crooked - and it wasn't just because I can't put things up straight! This meant that when placed into the corner of the shower, the shelves of the units sloped slightly. With the shelves on their own, it is not that obvious. However, with the horizontal and vertical lines provided by the tiles in the shower, it is clearly not straight!
Lastly, and only a minor thing, but one of the screws supplied with the unit did not have the grooves cut deep enough into its head. This meant that a screwdriver could not turn it and an alternative screw was required!
On the positive side, it is very functional, with a good amount of space despite the relatively small size. In addition, there is a good high bar on the top shelf so that bottles don't fall off easily!
I have only just started using it, so cannot say at present if there are problems with rust.