It is true & false...
SSD are just like a standard mechanical drive in the fact that once you install the OS & apps, you capacity may vary based on how it is setup with temp files, system restore for examples. In addition, OCZ had a much publized issue when they went to 25nm and lost capacity compared to the 34nm drives. It has / didn't effect all SSD's just a few capacities with OCZ Vertex 2 drives.
Where it is true is... If someone ever reach the point where they utilize all the write-cycles on the drive, it will basically become read-only and can no longer be written to. This would be basically lossing all it's capacity to a certain point... IMO
Basically, I would not worry about what you read on Newegg about lost capacity and move forward with your plan to purchase (hopefully) your new SSD.