The following table shows our measurement results, and we only listed one of each panel type (only 1x T490 and T490s) to simplify the table. You can basically say that all three panels meet the specifications from Lenovo since the manufacturer is rather conservative with its claims (contrast 800:1, 400 nits brightness) to avoid complaints. Our AUO panel just missed the advertised value of 400 nits, but it is still very close at ~390, and all three models easily surpass the advertised contrast ratio.

Still, there is one clear winner with the Innolux panel in the ThinkPad T495. Compared to the other two options, it manages much faster response times, which is also noticeable in practice. It also features more precise colors and the widest color gamut.

Update: The LG Philips panel in the ThinkPad X1 Carbon 2019 is behind the Innolux panel when we consider all the measurements, but ahead of the other two. The response times are slightly slower compared to the Innolux, but still acceptable. The factory calibration of the screen is unfortunately not very good and you will have to calibrate it for the full potential.