Two monitors can both say "27 inch, 1440p, 165 Hz" and still look very different on your desk. The difference is the panel type: the technology that actually makes the picture. For gaming there are three you will meet in shops: IPS, VA and OLED. None is "best". Each trades something for something else, and once you see the trade you can pick the one that matches your room and the games you play.
IPS and VA are both LCD panels. Behind the picture sits one big LED backlight that is always on. Tiny liquid-crystal shutters in front of it twist to let more or less light through. The catch is that a closed shutter never blocks all the light, so black on an LCD is really very dark grey.
OLED works differently. Every pixel makes its own light. To show black, a pixel simply switches off. That one idea explains most of what follows.
IPS panels keep their colours and brightness when you look from the side, which matters if you sit close to a big screen or share it with a friend on the couch. Pixels also change colour quickly, so fast motion stays fairly clean. The weakness is black: a typical IPS monitor has a contrast ratio around 1,000:1, meaning white is only about a thousand times brighter than black. In a dark room, a night scene looks a bit grey, and you may notice a faint "IPS glow" in the corners.
VA panels are the budget route to better contrast: typical figures are around 3,000:1, so dark scenes look noticeably richer than on IPS. Many are also curved, which suits a monitor you sit close to. The trade-offs are narrower viewing angles (colours wash out sooner when you sit off-centre) and slower pixels in dark transitions, which can leave a faint smear behind a moving object against a dark background.
OLED gives true black, so contrast is effectively unlimited in a dark room, and its pixels change state almost instantly, so motion is very crisp. The trade-offs are real, though. OLED monitors often cost more at the same size and sharpness. They can show a little less brightness when most of the screen is white. And because the pixels age, a logo or taskbar left on screen for thousands of hours can leave a faint ghost, a problem called burn-in. Makers add pixel-shifting and similar protections, but it is worth reading the warranty. Some OLED panels also look slightly greyer in a bright room, because the screen reflects the room's light.
The demo below is a simplified model using typical figures, not measurements of any one monitor. Drag the sliders and watch the dark parts of the picture.
Three things to try. First, leave the room dark and compare the black sky: OLED stays truly black, VA is close, IPS is a little lighter. Second, raise the room light: every screen lifts, and the gap between them shrinks, so a bright room takes away much of OLED's advantage. Third, slide your seat angle to the side: VA loses contrast fastest, IPS holds up, and the IPS corners start to glow.
If you play in a dim room, mostly alone, and love dark, moody games, VA or OLED will look best. If your room is bright, or you share the screen, or you also use the monitor for work and photos, IPS is the safest choice. If you play fast shooters where motion clarity wins, OLED and a good IPS are the strongest. If your budget is tight and your seat is right in front of the screen, a VA can look better than an IPS at the same price.
Keep in mind that panel type is only one spec. Refresh rate and resolution still matter, and a great panel at 60 Hz can feel worse in motion than an average one at 144 Hz. Our guide to refresh rate covers that part.
Around the lowest budget (roughly €100–200): a 1080p IPS or VA at 144 Hz or more is plenty. Check the panel type is listed, and that the size is not much more than 27 inches, because 1080p looks soft when stretched.
Mid budget (roughly €250–400): aim for 1440p at 144 Hz or higher. Choose IPS for versatility or VA for contrast, and look for adaptive sync (FreeSync or G-Sync compatible).
Higher budget (roughly €400 and up): OLED becomes an option. Check the warranty wording on burn-in, whether it is a glossy or matte coating, and that your graphics card can drive the resolution and refresh rate you are paying for.