Although it fulfills its promise of quickly finding any document on your hard drive, Instant Document Search offers few features to make it more compelling than other free options. Its initial indexing process takes a bit too long, although you can speed it up by choosing to have it only look at partial documents, such as the first 20KB, for instance. The search function supports logical operators such as AND and OR, but can't sort results by relevance. The fact it doesn't index e-mail puts it far beyond competitors from Google and Copernic. Instant Document Search works fine, but it's too limited compared to what else is available.