I have been using QGIS with an Apple Magic Mouse. Despite disabling all the point and click features and gestures in the systems preferences, the maps constantly zoom in and out extremely and uncontrollably with the merest touch of the cursor to the screen. What could be causing this?
Although still quite buggy you can change Qgis/ Preferences/ MapTools/ and than zoom factor. You can set it to 1.1
Under Settings / Options // Map Tools // Panning and Zooming you can set the "mouse wheel action" to "Nothing"
This can also be used if you are using slow data-connections (like a database) so your view doesn't get rendered with every roll you do on the mousewheel.