Picked one of these up the other day,
First one had a signal loss issue. The second one is working great. Tera, BF3, D3, WoW all work and look awesome.
I also don't get a screen until windows loads. My way around this is just keeping a VGA cable with the dvi adapter connected and swap when booting so I can see my boot screen and BIOS etc. (when I need it, otherwise dvi-hdmi)
Not a big deal to me as I've wanted one of these to replace my Hanns-G 27" 1080p for a while. My local MC sold through them pretty quick as well.
Have you tried displayport?
Also, are you able to drive the full res w/ HDMI?
Just picked one up from Microcenter. Unfortunately my rMBP does not drive this monitor at 2560 through the HDMI port. The hardware should be capable, but OSX is treating the device like a TV. I may try installing windows and experimentingl
In anycase, I have a mDP - DP cable on order from Amazon. I would have picked one up (or some combination of adapter + cable) from MC, but their displayport prices are outrageous.
My ancient lenovo laptop drives it at 2560 just fine via VGA. I'm going to try installing windows on my macbook and see if it can do 2560 from there
edit 3: Installed windows 8 and tried the monitor - connected right at 2560x1440 over HDMI. So OSX's HDMI support sucks (like the rest of its multimonitor support...)