After scouring the various forums (Ars Technica has quite a bit of good info here:
http://arstechnica.com/civis/viewtopic.php?f=19&t=1241859 ), and after a week waiting for Amazon to get stock, I finally bit the bullet and purchased the LG 34UM95 at Fry's Electronics. It is now connected to my Late 2012 Mac Mini using a Thunderbolt cable. Here are some notes:
1. I switched from a 23-inch 4-year old Samsung LED HD monitor. I have a pair of these Samsung PX2370s that I have used as dual and single monitors.
2. Initially, I simply unplugged the Samsung's HDMI cable and plugged in the LG via Thunderbolt cable without shutting down the Mac Mini. That wasn't a good idea. Only the top 4/5ths of the LG displayed properly; the bottom 1/5th was trying to scan but would not resolve properly. Restarting the Mac Mini fixed the problem.
3. The Thunderbolt cable is passing sound through to the monitor, and the speakers do work, but the speakers are not adjustable from the Mac (keyboard or control panel). The Sound control panel indicates that the sound output device is 34UM95, but that it is "Type: DisplayPort", and that "The selected device has no output controls". The volume can only be adjusted from the joystick at the bottom of the monitor. The sound is tinny with no bass, but that does not surprise me with built-in monitor speakers.
4. The Display control panel indicates that the display is running at 50 Hertz at 3440 x 1440 resolution, and you could also select 30 Hertz, but there is no option to run at 60 Hertz, even though I am connected via Thunderbolt. Switching to 2560 x 1080 changes the refresh rate to 60 Hertz, and there are no other options (the refresh rate is dimmed). The final available resolution is 2048 x 858 which only allows a 50 Hertz refresh rate. This seems very strange to me. Why would the lower resolution only be available in a lower refresh rate than a higher resolution, and why wouldn't the refresh rate be selectable. Savvier Mac geeks feel free to weigh in.
5. I am curious as to why I'm not getting 60Hz out of the Thunderbolt connection, so I checked System Profiler. As others have noticed, the Graphics/Displays panel of System Profiler is showing "Connection Type: DisplayPort" and "Television: Yes". It may be that my Late 2012 Mac Mini is somehow not able to push 60Hz, or that for some reason, despite the Thunderbolt connection, it is actually treating this as a DisplayPort connection and only allowing 50Hz, but the LG literature says it should push 60Hz even through DisplayPort. I have not found a resolution to this issue, yet, but the 50Hz refresh rate is okay for my use.
6. Despite the above, I am not having the issues described by user "tstm" here:
http://arstechnica.com/civis/viewtopic.php?f=19&t=1241859 . That user indicates that "OSX identifies this display as a television, and thus gives crappy color signal out. At least some gradients looked really poor. Some quick googling got me this handy bit of information on how to enable RGB mode and using it I got the colors to display as they should." User tstm was getting 60Hz out of a rMBP, but had to force RGB Mode (see here:
http://www.ireckon.net/2013/03/forc...ix-the-picture-quality-of-an-external-monitor ) because his rig was running in the YCbCr color space. I checked the ColorSync profile for my rig, and it is in the RGB color space, and the colors look good right out of the box with my rig.
7. The next step for me is to try calibrating the monitor with my ColorMunki, but that'll have to wait until I get some better ambient light.
8. One final note: Like many Mac users, I do not have an optical drive, and LG does not have software associated with this monitor on their website. Apparently that is a common complaint with LG. I may try to have someone create a disk image for me so I can install the software.
Hope that is helpful to anyone considering running this monitor from a Mac Mini. It works and looks great, but you may not be able to get 60Hz, even with Thunderbolt. If anyone has a fix for the refresh rate, please post a reply!