I love its easy usability and visual technology breakdown. It's quick and simple to use, with a ton of functionality. Great developer tool and competitor research tool.

Relatively easy to get a list build up and running. If you've ever used any other web based tool you'll be able to figure it out. Have recently upgraded the interface once you get your lists built that include new options like CRM format export but I haven't had a chance to use many of those yet.