Hey @macmesser!
On the Dell Peripherals forums, there are issues being raised about distracting horizontal lines, light leakage issues, color balance issues, and the U3014 monitor just not being usable due to its apparent flaws. Revisions "Rev a01" and "Rev a02" didn't fix the issues customers were having but it looks like "Rev a03" due out shortly -- if not already out -- looks to have possibly solved these issues.
I'm very happy for you that you haven't experienced these types of issues with your U3014. That's outstanding and, actually, reassuring to hear! Sorry about your current issue but I hope you get that worked out sooner than later. When I had my previous Mac Pro, my Dell 30-inch monitor was an absolute joy to use every day. It worked impeccably right from the off and I had no issues whatsoever.
Because I've had good success with previous Dell monitors up to, and including, the 30-inch versions, they were my first choice when deciding to get my new monitors. As someone who is looking to buy not one, but three 30-inch monitors, I get a bit hesitant when reading about these issues before having to make a decision to plunk down $3-4k on a set of monitors - especially since they're being purchased to help me with my business. I'm monitoring (no pun intended, okay, after writing it, maybe a bit) the Dell forums to see if the "Rev a03" really does solve the issues customers are having. If so, I'll probably go for three 30-inch Dell U3014s for my new desktop system. I'd love to have three 4k displays but, with current and seemingly near-future high price points over the next 30-45 days, the three 30-inch 2560x1600 monitors are probably going to be the go to purchases for me at this time.
Luckily, the new 2013 Mac Pro doesn't come out until December so that gives me time to wait to see what possible new monitors will be brought to market (as suggested by others, here) or getting the Dell U3014 monitors with the proper revision fixes. I'd absolutely love for the new Mac Pro to be out now but the next month or so, until sometime in December, will help me finalize better monitor options to get for my new Mac Pro.
