BTW: If you currently have an OS X 10.9.3 beta installed, per apple's OS X Beta Seed Program FAQ, "you can simply install the final version of the software you are testing when it appears in Software Update."
If anyone finds any significant pros or cons with their specific hw/sw, let me know. TIA.
FYI on 3rd Party Drivers/Addons: As with any OS update, it may break earlier 3rd party addons/drivers. Check the vendor/dev site for any updates. (One example was reported by a Caldigit USB 3.0 PCIe card user that said reinstalling the caldigit driver and rebooting helped. Here's CalDigit's USB 3.0 PCIe/Expresscard Drivers page. Thanks to FatMac/MacPro for the link.) If you enabled TRIM on your SSD, check its status after the update. (It may need to be reapplied especially if using a Combo Updater.)
Reports of 10.9.3 Problems with Multiple Displays: Just saw some early feedback in Apple's OS X Mavericks forum on external displays. A previous thread on 10.9.2 sleep problems w/NEC displays had some 10.9.3 positive feedback, but a thread on OS X 10.9.3 and multiple 30in Displays has some posts that only 2 out of 3 (or 4) are working. Some have already reverted back to 10.9.2 from B/U. (Try disconnecting/reconnecting (redetect) displays? or zapping the pram/nvram.)
"Re: 10.9.3 only lets me use 2 of my 3 30" displays
I am now seeing on multiple forums that others trying to run either 3 or 4 displays only get the first two working. I have reported this on bugreport.apple.com - suggest you do the same. Feel free to include my report number 16933298 in yours.
"10.9.3 update on MacPro1,1 with 3 Apple 30" Monitors
I have a 2006 MacPro1,1 that has been processor-upgraded and flashed to MacPro2,1. It is connected to three Apple 30-inch Cinema Displays.
The computer was running Mavericks 10.9.2 when I applied the 10.9.3 Combo Updater.
As with any update, it updates the boot.efi file in /System/Library/CoreServices/. So, after the Combo Updater was run, I replaced the boot.efi with the previous one that I had saved elsewhere. The other boot.efi file in usr/standalone/i386/ was not touched by the Combo Updater.
At this point, it is important to repair permissions prior to rebooting into the updated volume. (Repair permissions after the insertion of the boot.efi file.) Otherwise, the Mac Pro would not boot into the startup volume.
Then, I chose the original boot volume as a startup drive. Upon reboot, all three of my Apple 30-inch Cinema Displays were recognized and the Mac Pro booted into the same Desktop as before.
- Kunio M"