If you can live with 2k as opposed to 4k then Eixo CG 2730 is the best bet if you can stand the £1400 price. Beautiful colours and accuracy. Their 4k 32" version is over 4 grand if you have money to burn.
For a lower price I'd look at the Benq range, still good but according to internet experts the quality control isn't as good as the Eizo range, but they do still get really good reviews.
All depends on how important you view the colour management side of things and the resolution you require. Some of the Dell Ultrasharp screens can be excellent once set up and maintained correctly
Mike