I have a few PSP games which are now becoming quite rare, and the chances of replacing them are getting slimmer by the day. So it was a God-send when I discovered these cases. They were very cheap (far cheaper than a replacement UMD) and were delivered promptly. They also have a more robust build quality than the original Sony UMD cases (the perspex window being a single molding, and not a flimsy insert like the original design) so I now feel that the changed games are safer than the existing ones.
It was a simple process to swap the disc to the new case and the game worked fine as soon as I put it in the machine. As time ravages the remaining games in my collection I can see myself ordering more of these in the future.