Monitor recommendations 27"

Go for BenQ 4k HD LED Monitor. The monitor has some good feature which i most suitable for you including 3D features like CAD/CAM, animation, video editing and graphic arts.

I just won't risk Dell screens any more.  Check the Amazon user reviews.  They generally provide the largest number of people with real world experience of a product.  In this case it is better than usual for a Dell monitor, but be sure to read the low star ratings.  What it boils down to is tha if you get a good one, they are excellent value for money, but if you get a lemon, good luck with getting it sorted out.  You'll end up with a refurbished replacement that may, or may not have the same problems, but it will essentially be a used screen for the price of a new one.

With the 30" 16:10 screens I have been looking for, Dell had a roughly one in five chance of selling you a bad one.  The down side to this is that you have to pay a lot more for your peace of mind.  I have settled on an HP Z30i at significantly more cost.

I am glad you have not gone with an ultra high res screen.  At the moment, they don't work well with Photoshop because of the UI scaling.

Incidentally, are you keeping the two 24" screens?  I use a 30" main screen with a 24" screen in portrait mode on either side.  You soon get used to having so much screen area, and it becomes frustrating trying to make do with less, like using a laptop.  Carrying on with the Photoshop example, you can have a workspace with all major panels open, and with thumbnails set to Large.  With a 27" 16:9 main screen the 'H' shape of your workspace is going to be more exaggerated than with a 16:10 main screen, but with 1440 vertical pixels, the actual screen layout will be fine.    I use stands like this to free up deskspace.  These cost just NZ$64 and are worth every cent