It depends on the individual. Some people are sensitive to flickering colors / lights.
Amongst all the specific panel technologies, TN panels could be the worst for people with sensitive eyes. TN panels are cheap to manufacture and have low prices compared to more expensive panel techs. One reason why they are inexpensive to manufacture is due to the fact that TN panels can only produce 256k actual colors. In order to get anywhere near 16.7m color they must perform temporal dithering.
Temporal dithering is a process where the pixels in the TN panel quickly flashes between two colors to make a third color that it could not otherwise display on the screen. The colors flashes so quickly that it appears solid. For example, let's say a TN panel cannot actually display purple which it a combination of red and blue. What basically happens is that part of the screen will quickly flash between red and blue to fool the brain that you are actually seeing solid purple.
Other panels techs like PVA, MVA and IPS can actually produce 16.7m colors, but are more expensive to produce, especially certain IPS panels (S-IPS and H-IPS).
The other flickering is the florescent backlight. It looks like it is constantly on, but it is actually flickering very quickly. Generally speaking, florescent lights are not an issue for the vast population, but there always that tiny little percentage of people where the flickering can be annoying. Most LCD monitos use florescent backlight.
An alternative to florescent backlight is LED backlight. LED (light emitting diodes) backlight do not flicker to the best of my limited knowledge. It also uses less electricity than florescent and the monitor itself can be designed to be thinner. However, all LCD monitors that has LED backlight have TN panels.
LCD and TFT are bascially interchangeable terms.