Buy the LG 27GN800-B Ultragear QHD.

It is the better gaming panel, and the price gap buys you fewer headaches, not a better spec sheet trick.

What was compared

1. Dark scenes stay clean, not smeared
The LG's IPS panel keeps fast, dark scenes clean, with reviewers calling motion blur almost nonexistent. Samsung's curved VA panel is the technology best known for smearing exactly those scenes, and that shows up in every fast game you play.
2. Locked in for Nvidia, no compatibility gamble
The 27GN800-B carries Nvidia's official G-Sync Compatible certification, tested and guaranteed. The Odyssey G5 only lists FreeSync Premium, so Nvidia GPU owners are trusting it to just work without Nvidia ever confirming it does.
3. Colors look right, not just punchy
LG states 99% sRGB coverage, giving accurate color straight out of the box. Budget curved VA panels like the Odyssey G5 typically trade that accuracy for punchier, often oversaturated color, which matters if you ever edit photos or watch films.
4. Deeper blacks, but only if movies are the point
Samsung genuinely wins contrast, 2500:1 against LG's 1000:1, which looks great in a dark room watching films. But that same VA tech causes the smearing above, so unless movie nights outweigh gaming for you, that number never pays off on a 144Hz screen.
5. Yes, it costs more. Buy it anyway.
The Odyssey G5 undercuts it by about $140, real money. But research turned up recurring reported issues with the G5 that reviewers do not raise for the 27GN800-B beyond one isolated dead pixel case. Pay once, skip the returns process later.