It works, it's fun, has a HUGE community of millions of users - and can be overwhelming sometimes.
Cam Frog for OSX makes it a little too easy to drown in overlapping windows but it's very approachable for first-time video chatters to get connected quickly.
Nano Com morphed its code into ISPQ - and continues to provide a truly cross-platform videoconference app - for all of us.] Using Boot Camp, VM-Ware or Parallels: Mac users on Intel might try Windows PC options to give i CUii a looksee.
Recent improvements to the latest v3.0.2 version of Yahoo! The Mac version of Yahoo Messenger has a reasonably large community of users since anyone @can potentially video-conference.
Mac Skype, currently at Version 7.x is one of the most ubiquitous and reliable cross-platform video conferencing apps: It isn't just for free & very low-cost long distance Mac VOIP video and voice calling.
Check out and download the latest Linux video chat options.
The still VERY popular i CUii software once used it and was both Mac and Windows compatible.