I bought one of these, and after only a few weeks, the DVI input failed. Amazon immediately arranged a replacement, but when it arrived (with an opened box like others have reported), unlike the first one that had a perfect panel, it had a dead pixel and a double stuck sub-pixel (blue and green in the same pixel) near the centre of the screen. Incredibly annoying, but well within the ludicrously-generous ISO 9241-307 Class 1 limits that the AOC EMEA warranty works to. Within 12 hours, a vertical red line then started appearing intermittently near the right hand edge of the screen, so it's going back to be replaced by a Dell U2913WM. That monitor seems to have quality issues of its own too, but at least Dell will replace the panel if there are any stuck pixels at all. There's not really all that much choice right now in the 21:9 market, but as I'm replacing a pair of old 1280 x 1024 monitors, 2560 x 1080 works perfectly for me so I'm sticking with it.
I can see many other people who have had no issues, so maybe I just got unlucky. If you do decide to buy it for wall-mounting, though, be aware that with the stand removed and the back plate folded down, the bottom of the back plate is more or less flush with the bottom of the monitor. So, although you can hide any connection to the side of the back plate, you cannot hide anything that goes into the bottom. Like the power plug, for instance. The mounting holes are inset, too, so you'll need some spacers to fit between your mounting plate and the monitor. Really not well designed at all.