During one of our research activities the theoretical question came up whether finding the closest match in a color fan deck using RGB values would be different from using CIELab values. Obviously with the idea in mind that the Lab space would correspond better with human vision than RGB space.
This question occurred to us when we were compiling a report related to cheap color measurement devices to digitally search in color fan decks. These devices carry alluring names like Nano, Node, Nix, Capsure, Muse, Cube etc. A number of these devices work based on a camera CCD chip that determines RGB values like the Nano and Color Savvy devices.
We did not consider the Capsure although it also works with a CCD chip but illuminates monochromatically with 7 LEDs which makes a sort of abridged spectrophotometer. The manufacturers use the RGB values to search in a color fan deck. Obviously they optimize the results towards CIELab space and a modern criterion like dE2000 and they are quite successful in that. So the question if finding the best match in RGB space differs from finding the best match in CIELab space is actually only interesting from an academic point of view.