Easy to use - no search experience required.
Searching based on citation connections.
Ranking based on similarity according to collective intelligence.
Nice interface for reading patents and visual browsing.
Great export and sharing options.
Subscription based access.
Free trial available - half the results are hidden.
Once you have found one or more relevant patents, plug them in to get more patents that are similar.
This is a good way to check what you may have missed with a traditional keyword search.