I kind of want to just tell you "Meh" and leave my review at that...but I won't cop out.
My wife and I went there for brunch. The brunch menu is really just a breakfast menu. I tend to get breakfast at brunch anyway, but if you like to blend, you'll be out of luck. As for the meal, it was okay; middling, you could say. We had the Carnegie (eggs and filet tips), served in a cute dish with a handle. There was nothing wrong with the food, but it certainly didn't wow me. We also had the "pancrepes," which were just wafer-thin pancakes. We would have liked mimosas or something, but the first time I learned they were even available is from the reviews running next to this review I'm typing now.
As for ambiance, the place is sort of diner-y, but doesn't have the blue-collar feel suggested by a name like "Dahntahn." It's more like a yuppie's impression of a diner.
Lastly -- I'm not sure what can be changed about this, but the way the place is set up at the entrance is not particularly inviting. Maybe it's different at rush periods, but when we came in to brunch, no one greeted us at the door, even though there is a hostess station. Someone called to us from the other side of the bar which takes up most of the main room. It almost felt like we were intruding. Part of this is the close quarters and narrow corridor created by the large bar, but I think it's also a demeanor issue.