A big selling point for Adobe Connect is consistency across platforms. It's been authored entirely in Flash, so it's functionally identical on both Macs and Windows PCs (and, in theory, any other Flash-supporting platform).
The downside to having the whole application authored in Flash is occasionally running afoul of the limits of Flash's implementations in a given browser. The Adobe Connect Add-In, used for screen sharing (where one participant shares an active window on her desktop with everyone in the meeting) doesn't work by default in Chrome because of that browser's heavily secured implementation of Flash. You either have to change some internal Chrome settings or use another browser (such as Firefox).
Adobe Connect users are divided into three groups -- hosts, presenters and participants -- each with its built-in levels of privilege. (A host is someone who has complete control over the meeting; a presenter is selected by a host to talk or show slides.) The panels or "pods" displayed on-screen -- the video windows, the attendee list, the chat box, etc. -- are all replicated on each user's end. Pods are available for tasks like taking polls from the group, logging notes from just the presenters or the whole group, uploading files to be shared out to everyone, or taking written questions from participants in a moderated fashion.
The way pods are laid out on the screen is crucial, since everyone else in the conference sees the exact layout the presenter chooses. Icons down the right side of the screen let you select a few different pre-created panel arrangements: Sharing, Discussion and Collaboration. If you want to create your own layout for re-use, you can enter "Prepare Mode," which lets you edit the panel arrangements on your end; changes are not made live to everyone else until you say so.
The actual video chat portion of Connect has many of the features I've come to expect: follow-focus (switching the video feed so that whoever is speaking is given prominence), administrative control over cameras and microphones, etc. Unfortunately, my test of Connect seemed to be highly sensitive to geography: there were several seconds of lag between a speaker in New York and another in California, and audio and video tended to drift out of sync.
Connect's screen sharing function lets you pick a given app, window or desktop to share to the group, although it's one-way only -- you can't give control to another user. You can, however, place a shared item on a whiteboard and let others annotate it, which isn't a bad compromise. Some document types, like PowerPoint presentations, can be uploaded to the Connect server and shared out without the presenter needing the app for that document type.
Connect scores for its presenter- and presentation-oriented features, and for running on any Flash-supported client, although its video quality underperformed during my trial.
Adobe Connect's panel organization and sharing functions.