I owned this display for about half a day before returning it. I think you'd be utterly disappointed with it next to the Retina 5K display.
First off, the stand is so stupidly floppy that I couldn't even get the thing to sit level on my desk (which is level). Any key stroke on my keyboard would send the monitor jiggling around like jello. I have one of the higher end IKEA desks that quite stable.
Next up -- the screen. There is just no comparison next to the Retina 5K display. The iMac screen is beautiful, a real pleasure on the eyes with great color, contrast and viewing angles.
The Samsung is pretty much none of these things. While the colors are vibrant, they are less accurate and I actually found them somewhat harsh to look at. I didn't find it comfortable to look at this screen for long times. I was able to make this a little better by turning down sharpness on the screen, but I was never able to make it look very similar to an Apple display (Retina MacBook in my case).
Being a TN panel, viewing angles are pretty bad. The screen is big enough that this was obvious to me sitting dead center in front of the monitor. For example, if I was on a web page that had flat grey buttons on a white background, the buttons would be visible if they were in the middle of the screen, but would disappear if I moved the browser towards the edge of the screen. If I slouched in my chair, the lower viewing angle was the worst, turning my screen into boxes of black and white.
Finally, the screen coating and/or polarizing filter... gives the screen kind of a grainy look. I feel like I was looking at speckles of brightness and darkness. It contributed to the overall difficulty of looking at this screen.
I've been itching for a 4K external display from the day I picked up a Retina MacBook two years ago. I'm seriously just waiting to throw my money at the first company that makes a decent option that's not thousands of dollars. But, unfortunately, this monitor just wasn't it. The wait continues.
I'd strongly recommend passing on this monitor and waiting for decent IPS display. It looks like 2015 might finally be the year.
