I used to download a huge number of files from my college days, when I had not premium account on rapidshare. Then I purchased a premium account which is now being mostly used by my brother to download new movies with their latest release.
So If you have a rapidshare account whether a premium or any other account, Rapid Assist lets you convert rapidshare indirect links to direct downloadable links which can be then feed to your internet download manager.
Rapid Assist is quite useful when you have a premium account or collectors account or any other valid rapidshare account.