Yosemite is great and the latest Gold Master Candidate release is rock solid. The only missing piece for me was to integrate Mail with OmniFocus which I do numerous times on a daily basis.
According to The Omni Group, Apple has disabled some Mail plugin functionality in Yosemite that broke the Clip-O-Tron 3001 so I decided to whip up a small AppleScript to bring the currently selected message into OmniFocus as a task.
You can grab the gist of the script on GitHub.
Feel free to send pull requests. Hope you enjoy this interim fix until The Omni Group fixes the Clip-o-Tron.