As I'm leaving Pgh in a few months I've queried the locals here about my restaurant list before I leave and a lot emphatically said Legume. Now I'm another of the 100+ reviewers that was "Wowed!" by Legume. In some sense I won't miss Legume as there are hundreds or thousands of these types of restaurants around the country. In other senses it's a tremendous value for the creativity, execution and taste.
My awkward comparison of Legume is with Daniel Boulud in NYC: both restaurants are the few in my recollection that hit it spot on from appetizer to dessert. No lulls, no "meh"s, not a lot of fluff as similar restaurants, nothing to nick-pick worth mentioning.