After having used other conference calling services in the past, I like that UberConference offers a free alternative for small businesses. VoIP integration, simple screen sharing, and recording options make Uber Conference a must have for anyone doing web-based presentations. Another great feature is Uber Conference's post-call transcript, where they make the recording from the call available via a downloadable audio file.
The only negative is that the screen sharing options are only accessible to users running Google Chrome as their browser. The requirement is that the presenter is using the Uber Conference Google Chrome Extension.
Having only used Uber Conference for a few short weeks (probably a month), I think everybody should consider Uber Conference because they offer a permanently free level of service. There are upgrades available for larger companies, but we've found the free version to be fully functional.
I've used (and continue to use) TeamViewer for web demos, and while it works, it can often be clunky and require extra steps for the participant. We've never upgraded to use TeamViewer's VoIP audio, so the call portion was never connected to the video, which made recording difficult. With Uber Conference, I can now easily record sessions.