Originally Posted by Arup
You have no worries with the xorg update in that ppa, if it applies to your distro, there is a reason for it, also this ppa is for stable releases and not cutting edge so you can be rest assured that issues shouldn't arise normally.
I dont have since i use Debian... But i did mess up a few times in Ubuntu my dependencies by adding various PPAs that offered updates for key system packages out of the main repositories. I had to redo everything steb by step.
I reckon apt-pinning might help, but the problem is that everything is just put in "main" and filtering packages from larger repos is time consuming.