I'm currently using 2 monitors. U2410 and U2913. However there're some problems with the DP on my U2410.
Issue 1. Using only U2410 with DP, after power off the monitor, I won't be able to power it on again. Have to unplug the power cord and plug it again to have the monitor work. PS: this happens even under Windows
Issue 2. Setup up duo monitor with DP. Every time I setup extended desktop with these 2 monitors, the resolution will go down to the default value, like you didn't install the graphic card driver. I have to manually adjust the resolution every time. However, U2410 with dvi works fine. I also tried to use my U2913 with apple 27' display and it works fine as well.
Basically I called the so called "technical support team" and the person there knows nothing about this. What he did is just read things from their "database". He even didn't know the difference between monitor size and resolution. And he kept saying it is my graphic card's problem. Well, I don't think a 7970, a GTX780 and a Titan would have exact the same problem...