There is absolutely no replacing a professional grade monitor when editing photographs, color grading 4k video footage, or laying out a visual centric blog such as this one; but it is far from realistic to carry around my 27" Apple cinema display in a Pelican case from destination to destination when you travel as much as I do. But likewise, it is also very impractical to wait until I get home to start work on these, often times, time sensitive edits; specially when "getting home' is sometimes MONTHS away.
My 15" Macbook Pro Retina (mid 2012) has been a rock solid piece of gear since the day I brought it home and it solves ALL of these problems for me. The screen's brightness and resolution actually EXCEED my cinema display; and, while 15" is not an ideal size, it is the perfect weight compromise when traveling as it fits in most professional cases and camera bags quite securely. I have grown quite accustomed to editing on this screen and actually prefer it to the cinema display when editing photographs for sure. The images look more like prints than digital representations, more so than any other screen that I have ever worked on.
The generations of Retina screens that have followed on MacBook Pro's MacBooks and MacBook Airs have continued to provide impressive displays, suitable for professional work, but as of 2017, it is only the MacBook Pro that provides adequate power to edit 4K video on the road.