The former Denien's site on Marrett Rd in Lexington is now Formosa Taipei, a mostly takeout chinese restaurant, with a Taiwanese slant.
I gather the owners used to own, or part own, Jo Jo Taipei in Allston.
Don't know much about Taiwanese cuisine, but I enjoyed pan fried pork buns, sticky rice with pork in bamboo leaves, hot and spicy minced chicken (pretty spicy!) and got a bag of pork and cabbage dumplings which I havent tried yet, but look good.
They also bought the bubble tea equipment from the former owners, and are shaving ice and making bao bin, which I didn't try, but looked good and was being bought up by many chinese customers.
Maybe someone with more experience can chip in.