iMac Retina 27 Display vs. NEC MultiSync P221w

I have been using an NEC MultiSync P221W display for editing photos in Lightroom for years. However, I recently purchased a new iMac Retina 27. Although I have not calibrated the iMac yet, I am curious how the iMac's display might compare to the NEC in post processing. I would really appreciate your thoughts. Thank you kindly.

I had an NEC and as you noticed the screen has a flatter look to it because it is designed for pro editing. Mac has a shinny screen which I don't mind.

Not sure what you used to calibrate your NEC with but the only successful product I found was Spectravision. For my iMac I purchased i1 Display Pro and I think the colours are as accurate as my NEC was. The NEC's bulbs just got too weak so I turfed it.

I think you will find the 2017 iMacs are calibrated to DCI-P3 at the factory and should be very close to that at your home. The question is...do you DCI-P3 the video standard or AdobeRGB which is another wide gamut standard?