Samsung UA40H4240AR features a 40 Inch (102 cm) screen while Samsung UA40J5100AR comes with 43 Inch (109.22 cm), which can make a noticeable difference depending on your room size and viewing distance. Samsung UA40H4240AR and Samsung UA40J5100AR are well-equipped smart TVs that aim to provide a balance of picture quality, performance, and smart capabilities. From a practical standpoint, both options provide a reliable viewing experience for most users. Both TVs offer adequate brightness levels suitable for most indoor lighting conditions. Both TVs provide decent motion handling, making them suitable for everyday viewing including sports and action content. Samsung UA40H4240AR and Samsung UA40J5100AR differ in resolution (1366 x 768 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. Both TVs come with smart platforms that support popular streaming apps and voice control features.

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