I had purchased a set of boots that retailed for $600, and I knew that my other "casual" ski boots had been so chewed up from the stone parking lots and concrete that I needed something to protect my good ones from the same fate. Even if I was walking on a snow-covered lot, I could still feel stones grinding on the bottoms of the boots. I had seen others with these on, and wondered if they would be worth it.
Be sure to read the mondo and mm size of your boots and compare against their chart for ordering the correct size. When I received them, they appeared to be quite rugged and made with durable rubber. They are a snug fit for my 28.5's, but that will help keep them on. What some other reviewers might not realize is that you need to have the rubber cup on each end of the Trax completely over the binding lug on the boot so they don't come off. That is the only difficult part of their use.
These make walking in ski boots more comfortable, and almost provide a feeling like you're rolling your foot just as you would in a normal shoe. They absorb shock and provide traction on ice and terrain. When not in use, they fold in half and stow easily in cargo pockets and are lightweight.
For the benefits they provide, I would have no qualms about buying these again.