I have yet to see a thread of this kind, so I thought it might be helpful. I realize some users will be using 10.9 without a developer account, I have no opinion on the matter. However, it might be beneficial for such users to relay any bugs that developers can report to Apple engineers. I usually spend a day or two reporting a list of bugs as it takes some time and the more information Apple receives the better the chance at improving the OS. Thanks! *As pat vas pointed out, I will attempt to reproduce bug reports on my systems: - Curgent gen Mac Pro 5,1 w/ 2 27" LED LCD's (for those with multi-display bugs) - 2012 13" MacBook Air - 2012 MacMini used as a HTCP - 2011 iMac I have most systems covered. If you are willing to follow up with me should engineers request, that would work. Most often, unless the bug is widely reported or serious in nature, engineers will acknowledge a submitted bug and will work on the matter without further action from the developer. Minor bugs such as UI suggestions are usually done without further follow-ups. Submit reports in this format.