I used a TN display in vertical position for a while and it sucked. If you moved the head just a little sideways the colors completely changed, and after a couple of hours I started to feel nausea. My doctor told me it was because the eyes are seeing different images (each eye saw the display at different angles, and because of the poor vertical view angles the brain received different colors and light and had to compensate - like using polarized 3D glasses). Now I use a combination of vertical + horizontal 16:10 IPS displays and it's way better. I mostly use the vertical one for web browsing and doc reading.