4k Monitor for my PC



If I increased my budget to $600, would there be any better monitors? I'm looking for around 27" or more. It would be great if you gave me about 2-3 options please.
 


Here's a 28 inch monitor. It has a 1ms response time which is amazing if you want to do any type of gaming.
http://www.amazon.com/gp/product/B00YD3DBOC/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B00YD3DBOC&linkCode=as2&tag=toxislay00-20&linkId=XF7XSI3O5MPCFY7M

This one is a little bigger (31.5 inches) and curved if you're interested in those types of monitors. The response time is 4ms which isn't as great but still good compared to most monitors. It's also a little cheaper than the first.
http://www.amazon.com/gp/product/B00WBWTW1I/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=B00WBWTW1I&linkCode=as2&tag=toxislay00-20&linkId=OZJQQVPJMX6SOO5D
 


Thanks a lot!