Jason, I've bought four Korean monitors (all four were achieva shimians) and only one of them was absolutely perfect. The other monitors suffered from dust under the glass, dead pixels, or just complete malfunctions where the whole screen was flickering green, etc. Honestly, if you're saving up money to buy a single monitor to last you a long time, I wouldn't put your money on the Korean brands. I would stick to domestic with an easily usable warranty. It is easily pushing 100 dollars to send a monitor back over to korea for warranty services.
You'll just have to make a choice between 1440p or 120hz, or maybe you'd be fine with 1200p IPS. You have to see each choice and make a decision that's right for you. I've had plenty of different monitor set ups, but I've gotten the most mileage out of dual 1080p displays. I currently use two 120hz panels and it's lovely. But that may not be the right choice for you. Monitors are highly debatable as to what is best.