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. Westinghouse WD43UB4530 and TCL 40S351-CA are well-equipped smart TVs that aim to provide a balance of picture quality, performance, and smart capabilities. There is a difference in screen size (43 Inch (109.22 cm) vs 40 Inch (102 cm)), and a larger screen generally provides a more immersive viewing experience. Westinghouse WD43UB4530 and TCL 40S351-CA differ in resolution (4K 3840 x 2160 vs 1920 x 1080), which can affect overall clarity and sharpness of the display. Both TVs provide standard built-in audio performance suitable for regular usage, though external speakers can enhance the experience. Overall, both models are capable choices in their segment, offering a balance between performance, features, and usability. Both TVs provide decent motion handling, making them suitable for everyday viewing including sports and action content.

Verdict: Both models offer good value, and the better option depends on your specific requirements and viewing preferences.