I concur ... the background gives the image an overall feeling of warmth (which, of course, is not achieved with the white shirts) ... I like the natural expressions and pose ... I could easily see this framed as a horizontal or a vertical ... I could see it cropped tight on the faces for a close-up, as well.
excellent portrait. love the colors and light and tones, and their happy faces :) like the vignette also. it obviously has a slightly staged look in that they came to this place to have a portrait taken, but it doesn't look forced or unnatural either. they certainly look genuinely happy to be standing there together.