Both TVs provide decent motion handling, making them suitable for everyday viewing including sports and action content. Both TVs provide standard built-in audio performance suitable for regular usage, though external speakers can enhance the experience. Intex LED-3900 and Intex LED-4200 are two competitive smart TVs offering a mix of display performance, smart features, and overall value for different types of users. Both TVs offer adequate brightness levels suitable for most indoor lighting conditions. Overall, both models are capable choices in their segment, offering a balance between performance, features, and usability. Both TVs come with smart platforms that support popular streaming apps and voice control features. Both models support 1920 x 1080 resolution, ensuring sharp picture quality with detailed visuals for movies, shows, and gaming. Intex LED-3900 features a 39 Inch (99 cm) screen while Intex LED-4200 comes with 42 Inch (107 cm), which can make a noticeable difference depending on your room size and viewing distance.

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