That I cannot tell you - on their respective tech specs pages, they both show the exact same thing for the display/resolution:
https://support.apple.com/kb/SP707?viewlocale=en_US&locale=en_US
https://support.apple.com/kb/SP718?viewlocale=en_US&locale=en_US
So, it could have to do with the graphics card since one of those is available with an upgrade option for a better one.
As for "stunning" - yes, they do, but when you put aside the wow factor and get down to actually needing to see what is on the screen looking at emails, documents, etc. - to me, that is what counts. So, whatever "fits" you and your eye(sight) is what is important.