Have been using the non-magnetic versions for years, magnets are a definite improvement. I work in a marine environment and move the tool boxes around constantly which keeps the tools moving around in the boxes (we are not always gentle with the box and putting them on moving boats doesn't help).
All plastic is great due to rust issues, easy to clean and the magnets keep the rails from going anywhere when the boxes are moved. The colored rails help when directing other to get things from your box.
The best I've found so far.