This is mentioned in U2311H spec:
Coverage (sRGB 100%)
But it doesn't mention anything about AdobeRGB, what does this mean?
At $299, it is worth every penny for the price.
sRGB is still the standard for colour rendition. AdobeRGB is the expanded colour space being adopted by most people nowadays. However if you use AdobeRGB and when someone else view it in sRGB, the image tends to look dull. If you edit in sRGB, the image will still look the same in AdobeRGB.
You can read it here at Ken Rockerfella.