It actually works fine with DP and with native resolutions, otherwise it's not sharp, but the resolution could be a problem. This monitor has different resolutions than an iMac 27". For example: the standard is 2560x1440 for iMac, this monitor can't do that. With different resolutions, everything is different sizes. With some applications it's less of a problem, but in my work, with a lot of text reading, it bothered me.

Much better via DP than via HDMI. I use it as a second screen for my MacBook Pro 15 via a docking station.