Somewhat late, but eventually it helps other People:

I am using 3x 24" TFT Screens in Portrait Mode, so nearly 4k Resolution (3800*1920). As I am working in the IT Business please pay Attention to:

- IPS Panel (better view angle)
I currently have the Problem that my tfts are non-IPS and they are designed to look at them from above the Center line in landscape mode. So when mounting them in Portrait mode I am not looking at them in the correct angle to get a real nice Picture. I Need to move my head to the right side to get the full bright Picture due to the restricted view angle.

- factory calibrated Display
When you use NVIDIA Surround your Display will be seen as one single Display, so you are unable to calibrate the single Displays inside Windows using DataColor's Spyder. I have got the Elite4 myself and can calibrate the Displays if not using Surround - so they are looking exactly the same from brightness, contrast, Colors, whitepoint. Activate Surround and the calibration is gone.

These two points are for sure more important than size and reaction time. Reaction time should not be a problem today. I have even tested with 3x 22" in landscape mode - would be sufficient for me, too. But these two Points are really disturbing me - thank God I didn't pay much for these 3 used displays.