This is our go-to Au Bon Pain downtown. As with any Au Bon, I'd recommend the grab-and-go options (bagels, yogurt parfaits, danishes, etc.) over their other offerings. If the lines are short, the sandwiches are okay, but I don't think they're worth the wait.
This particular location is small, and while the bakery goods are usually stocked pretty well, the cold items (like yogurt, etc.) are really hit-or-miss. I can't count the number of times I've gone here looking for their greek yogurt parfait and the shelves were bare. There's no rhyme or reason to when the shelves are stocked, either.
The saving grace for this location is the staff, which is generally very nice, but service can be slow and the checkout lines can get long very quickly when too few people are on the registers to handle the rush (this is a common occurrence at this location).