The LG C4 OLED 55 outperforms the LG Nanocell 75 NANO75 in contrast and motion handling with perfect blacks and 120Hz refresh (per RTINGS reviews). The NANO75 provides a larger 75-inch screen at potentially lower cost but suffers from washed-out blacks typical of IPS LCDs. C4 is the stronger pick for cinematic viewing while NANO75 suits bright-room casual use.