Before uninstalling, please open a support request to let us know why you are not satisfied with ooVoo. Hopefully your issues can be solved quickly.
To uninstall ooVoo, follow the instructions ‘Fini111’ wrote. You can easily remove the ooVoo.app file. Aside from this, some ‘ooVoo’ folders are created in order to store your video messages, recorded video calls and received files which were sent to you. You can select 'Preferences...' from the 'ooVoo' menu and then go to the ‘Video messages’, ‘Recorded calls’ and ‘Received files’ tabs to locate the folders. You can also use your file search tool on your MAC to search for ‘ooVoo’ folders (‘Fini111’ mentioned clicking on the Spotlight icon).
Best regards,
Marvin