This would probably be the overall reason. I can only speak from personal experience but I bought one of these Korean monitors about 2 years ago and I'd never buy another one.
The picture quality is acceptable and it was cheap, but they're about the only positive things I can say about it.
- The build quality is cheap and plasticky
- I've noticed an increasing number of stuck pixels cropping up recently
- There's a small group of dead pixels near the top right corner
- When turning the monitor on I'm frequently confronted with a mass of coloured lines on screen, forcing me to turn it off then back on again.
- The main issue I have though is the terrible coil whine which sounds in perfect synchronisation with the flashing power LED when the monitor goes into standby mode.
Agree the build quality isn't great but it's good enough for me - the stands though are awful (I've had Yamasaki Catleap and Qnix Q270) - VESA mounts are the best solution but for some reason they've made it really awkward to fit them.
I also hate the stupid flashing LED - I disconnected the Catleap's one altogether when I took off the monitor housing to remove the crappy stand LOL. With the Qnix I just put black tape over the light (same as on my headphones and PC) - why oh why do manufacturer's think it's a good idea to have a plethora of blinking (blinking)
lights on everything, especially when the item is either a) working (I know it is, I'm using it) or b) sleeping (in which case, STOP BLINKING)!
Apart from that I've been lucky so far, only having 1 stuck pixel (Catleap) and some backlight bleed (Qnix). Picture quality (Glossy IPS screen) is lovely and I got 100+hz on Catleap and 120hz steady on Qnix (could probably do more but it'd be a bit pointless). There is some artefacting (blue lines) on video @ 120hz so I usually leave it @ 96hz. Also hardware video acceleration on the GPU has to be turned off when viewing flash or you just get blue screen.
No coil whine I can hear in my case though others have had really bad issues with it...
Definitely fun to play with but not for serious business really - I'm just glad they've had an effect on the market and maybe even brought the prices of IPS 27" 2560x1440 screens down in general...
Edit: Oh forgot about the reduced brightness when overclocked, though that doesn't bother me personally.