It's easy to use with detailed information on functionality & how to use. This includes 'how to' videos, knowledgebase and an idea forum for feature requests. It's also easy to submit issues/questions concerning sales and/or support.
It's easy to see what Cirrus Insight does. It's a web app (it says coming soon for iPhone and iPad) that integrates Salesforce with Gmail as well as with Google Calendar and Google Contacts. It's easy to get more information on the features and pricing pages, and it's obvious how to install the app for a free trial and how to sign up after the free trial.