I think you could have a good site on Squarespace. Really it can be used for anything, it is just tailored design-wise a little more to artists, graphic designers, etc. But, they have some good looking themes and something like their Adirondack and Bedford templates could work well for a mediation/attorney service site. Ocoos is a solid option if you would be willing to pay Ocoos for their professional website build package, which would definitely look slick when they were done. Or, Weebly could be good too.
Hope that helps!