I like that it integrates with many different tools/systems so you don't have too much work doing one-off pieces of software integration.
The interface is very easy to use once you get used to how things connect together (which in my case took 2 weeks). There's not alot out there right now as far as these types of products go - this seems like its going places! They also do other services, but we are using them solely for our recruiting process at least in part due to their ability to provide quality reporting data from across multiple job sites.