I first became a fan of his from the wonderful book. Part of my background is as a frustrated 2nd unit cinematographer(special effects photography). He was also a good photographer, and his layout was designed with photography in mind. His lighting, backgrounds and use of mirrors was brilliant. He never allowed people to smoke near his layout for fear of altering colors, gumming up the track, or coating light bulbs with that thin layer of tar. John Allen single handedly changed how people did model railroading from trainboards to the advanced construction we use today. George Sellios' layout has a similar 'look' to it but he has the advantage of 30 years of progress, technology etc. While JA's layout doesn't always look 'real' is does have a magnificent grand look.
On the other side of the spectrum was Jack Parkers layout. His modelling was sparse, but he followed prototype in telephone pole spacing, and his layout also had a specific 'look' to it, of the northwest, with the cloudy sky, obvious recent rain and such. Much of the illusion is from the scenery and background and how well it melds with the track work and structures.