We have been seeing this trend a lot at the salon I work at, Gordon Salon in Wilmette, IL.
The best way of achieving The Sombre (soft or subtle ombre-or as a coworker referred to it as the Mombre! When I got one!) is in using more colors in the blending; keeping the darker tones found at the roots, then subtly weaving it through the lengths of the hair with more of the lighter color found on the ends still. But, ultimately creating a much less abrupt contrast from the roots to the ends. Balayage is the best way to create this look.
The Sombre trend can work for almost anyone! The beauty of it is that the roots can be kept natural and do not need to be redone for up to 6 months, or you can just retouch the root for grey coverage for the following appointments. Using tones that are closer in color to your natural color base are the most complementary for your skin tones. So keeping a bit lighter or darker from the base color helps to achieve this look.