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 4K 3840 x 2160 resolution, ensuring sharp picture quality with detailed visuals for movies, shows, and gaming. Panasonic TH-58HX450 and Samsung HG55AT670UJ are well-equipped smart TVs that aim to provide a balance of picture quality, performance, and smart capabilities. Panasonic TH-58HX450 features a 58 Inch (147 cm) screen while Samsung HG55AT670UJ comes with 55 Inch (139 cm), which can make a noticeable difference depending on your room size and viewing distance. Panasonic TH-58HX450 and Samsung HG55AT670UJ offer different motion rates (60 Hz vs 100 Hz), which can impact smoothness during fast-moving scenes like sports and gaming. Both TVs provide standard built-in audio performance suitable for regular usage, though external speakers can enhance the experience. Both TVs offer adequate brightness levels suitable for most indoor lighting conditions.

Verdict: Choosing between Panasonic TH-58HX450 and Samsung HG55AT670UJ depends on your usage, whether you prioritize display quality, smoother motion, or smart features.