Besides protecting the discs and minimizing storage space, a CD storage soutions has to be ergonomically correct and efficient. That means the CD has to be accessible quickly and easily.
Many storage sleeves use a "bull horn" cutout that makes it especially difficult to re-insert the CD because the disc frequenty gets caught on the flaps of the cutout.
Another often forgotten aspect is the orientation of the opening. Most sleeves use a top opening beause it is the most simple way to manufacture the holders. However, in a typial usage scenario the storage container is held with one hand and the other hand will insert/retrieve the CD. The most natural movement is to slide the CD in/out horiontally. This requires a side opening that can only be found in CD Storage Sleeves from DiscSox.