TCL 4 Series 55S421 55-Inch 4K UHD HDR Roku TV

The TCL 55S421 puts a 55-inch 4K UHD panel with HDR support in front of Roku's smart TV platform — a combination that solves the two most common frustrations with budget televisions: mediocre resolution on a large screen, and a clunky or unsupported smart TV interface. At 55 inches, the jump from 1080p to 4K is visibly meaningful at a typical couch-to-TV viewing distance, and HDR support ensures that the growing library of HDR-mastered content on Netflix, Prime Video, and Disney+ displays with wider contrast range and more vivid highlights than SDR. The 4K Creative Pro upscaling handles the majority of non-4K content — live TV, 1080p streams, older media — by processing it to better suit the panel's native resolution.

For most households, this TV's strongest practical feature is Roku. The platform is straightforward to navigate, supports virtually every major streaming service, and receives automatic software updates that keep it functional long after purchase — something proprietary smart TV OS platforms often fail to deliver. Setup is minimal: plug in, connect to Wi-Fi, sign into your Roku account, and streaming apps are ready within minutes. The trade-offs are in the panel technology: the 4 Series uses a standard LCD panel without local dimming, so in dark rooms with high-contrast content, black levels and HDR peak brightness fall short of what TCL's higher-end QLED and Mini-LED models deliver. For brightly lit living rooms and everyday streaming, it performs well above its price; for cinephile dark-room viewing, the panel's limitations become apparent.