TCL 55C728 and Haier H55K800UG offer different motion rates (120 Hz vs 60 Hz), which can impact smoothness during fast-moving scenes like sports and gaming. Both TVs offer adequate brightness levels suitable for most indoor lighting conditions. Both TVs come with smart platforms that support popular streaming apps and voice control features. Both models support 4K 3840 x 2160 resolution, ensuring sharp picture quality with detailed visuals for movies, shows, and gaming. TCL 55C728 and Haier H55K800UG are well-equipped smart TVs that aim to provide a balance of picture quality, performance, and smart capabilities. Both TVs come in similar screen sizes, making them suitable for comparable viewing setups and room environments. Both TVs provide standard built-in audio performance suitable for regular usage, though external speakers can enhance the experience. In general, both TVs cater to modern entertainment needs, including streaming, gaming, and everyday viewing.

Verdict: Both TVs are strong contenders, and your final choice should depend on your preference for screen size, motion performance, and smart features.