We used the old version of Symantec which was altriris. We chose Service Desk because CA had the best grasp of EITM at the time (2009). The integrations for ticket creation and cmdb with Spectrum and event monitoring tools was very attractive.
While the concepts of Service Desk and EITM were solid. The user interface, tool capabilities, and integrations fell behind the rest of the industry. Too often it seemed like CA bought and rebranded products without fully integrated them with their other products. It was a coat of paint, without the parts under the hood being updated. The overhead for administration was too high and the reporting capabilities were absolutely amongst the worst I've seen.