Ended up having a pretty good meal at M Henry - thanks for the advice everyone!
We arrived at about 1:30 and I think the timing was perfect, because the restaurant was completely full, but there was no one waiting for a table. We told the hostess we were a party of three and in about 2 minutes we were seated at what appeared to be the only open table in the restaurant.
I went with the egg sandwich, and though it was very good. The eggs were cooked to a perfect over-medium (I know some people have had issues with this up-thread), the bacon was crisp, and the bread well toasted. The gorgonzola was a nice touch, though I think it was a bit low-quality, as it was not very creamy and quite crumbly - still, it tasted alright and nicely cut the richness of the bacon and eggs. The bread, while toasted well, I thought would have used a little butter (or more butter?) as it was a little dry. The potatoes were perfectly cooked and I liked the onion, green onion, red pepper, and garlic blended in.
My brother had the empanada special with some sort of chicken filling, along with a bowl of the Portugese kale soup. This meal was a little odd, because the empanada was literally just a single empanada (granted, a large one, made of pastry dough) on a plate with some sort of green leaf garnish. It looked a little lonely on a full sized plate, with no salad, slaw, starch or any other item to accompany it. Still, despite the odd set up and inauthentic preparation (pastry dough) he liked it. The soup was also a bit odd. When I hear Portugese kale soup, I immediately picture a cloudy, kale-packed soup with slices of Portugese sausage. This was more like a bean chili - with garbanzos and black beans, in addition to a relatively scarce amount of kale and chorizo. Still, as with the empanada, despite it being different than expected, he really enjoyed it.
My mom had the open-faced harvest sandwich, which she loved. Granted, she is a suburbanite empty-nester, who usually doesn't go out to eat very often, so almost anything she gets she always loves. Still this was definitely the prettiest, and most unique dish of the afternoon. The sandwich had roasted beets, goat cheese, spinach, and pecans - dressed in a vinaigrette. She selected the plantains as her side and despite the trend we saw through most of the meal of M Henry doing very odd takes on Latin American standards, the plantains were right on point - caramelized, cooked perfectly with great flavor.
And what else could we end the meal with but an order of blackberry bliss cakes to share? It was the perfect desert - the best part of the meal, but decadent enough where I was glad I didn't order it for my main meal. Rich but not too sweet, incredibly fluffy pancakes with fresh berries and a tasty vanilla mascarpone that was a welcome change to the normal whipped cream and/or powdered sugar you usually see.
Service was great, very friendly and attentive - we always had our waters and iced teas refilled without having to ask.
I enjoyed the meal and, while there were a few things that could have been a bit better, can see why the place is so popular. Waiting an hour to get in during brunch rush? I think not. But, as a fun destination for a late brunch or lunch when in the area - absolutely.