TCL 55S451-CA and Mi TV 4 PRO 55 differ in resolution (UHD vs 4K 3840 x 2160), which can affect overall clarity and sharpness of the display. TCL 55S451-CA and Mi TV 4 PRO 55 are well-equipped smart TVs that aim to provide a balance of picture quality, performance, and smart capabilities. Both TVs offer adequate brightness levels suitable for most indoor lighting conditions. From a practical standpoint, both options provide a reliable viewing experience for most users. Audio output differs between the two (10 W + 10 W vs 2 X 8 W), which can influence overall sound clarity and loudness. Both TVs come with smart platforms that support popular streaming apps and voice control features. Both TVs provide decent motion handling, making them suitable for everyday viewing including sports and action content. Both TVs come in similar screen sizes, making them suitable for comparable viewing setups and room environments.

Verdict: Choosing between TCL 55S451-CA and Mi TV 4 PRO 55 depends on your usage, whether you prioritize display quality, smoother motion, or smart features.