Maureen and I had dinner last night at the new Mezcal's on Fifth Avenue (the one that just opened, between 6th and 7th Streets). We shared a quesadilla as an app and a fajita as a main course and found the place and the food to be just fine, both in quality and in quantity. We asked for six tortillas with the fajita (one of the special fajitas, forgot just which one), and easily had enough food for the both of us.
They make a decent margarita and serve Dos Equis by the pitcher, as well as stocking several more Mexican beers in bottles and cans.
This Mezcal's has a backyard to which everyone gravitates, but we stayed in the small dining room and enjoyed it. When we sat down we were the only diners in the dining room (although the backyard was full), but when we left, there were no open tables. We found the staff to be quite friendly and prices are very reasonable.
To us it is noticeably better than the other one on Fifth Avenue near Union. We're curious to hear what others think.