First, a disclaimer: I've only had lunch at Gregoire's (I'm on a student budget, so I haven't splurged for dinner, which is about twice as expensive), so my review only applies to the lunch offerings.
There is something about Gregoire's that keeps me going back. Maybe it's the sight of fresh, organic ingredients being expertly prepared in the closet-sized kitchen. Or those hexagonal cardboard boxes that every sandwich or salad comes in. Or the ever-changing menu, which is completely re-written every month. In any case, I make it a point to stop by at least once a month to try the latest offerings. They're not particularly filling as far as sandwiches go, but they're usually good, sometimes great, and rarely just OK.