I have eaten at Virgil's in Times Square and Sylvia's in Harlem, and Daisy May's is definitely on a similar level in terms of quality. Now of course as you would expect with the name, they focus strictly on bbq - you won't find catfish here. But they do have some interesting twists. I had the smoked barbecued turkey leg, and it was perfectly cooked, and succulent - I should've gotten two!
I like the sweet tea, although you definitely should water it down with some ice, because it is quite concentrated.
As for the dining room, it is minimal - this is mostly a take-out joint. But I found the atmosphere there lots of fun. I heard some visitors from the south talking about how much they enjoyed the food, which to me is the ultimate compliment when you are talking about bbq!