Looking for webinar reviews

We are trying to find the right webinar host software to use for hosting online workshops with educators and are looking for some suggestions/opinions. These are some of the current options we've collected:

Elluminate

Cisco Webex

DimDim

Adobe Connect

GoToWebinar

Do you have a favorite webinar software for hosting or have you had any good/bad experiences attending a webinar on one of the hosts listed?

Thanks!