The latest review on Boston's Hidden Restaurants is that of Pho Yuen Dong in Quincy. Pho Yuen Dong is quickly becoming my favorite Vietnamese restaurant in the Boston area (with all due respect to Apsara in Providence, which may be the best I have been to anywhere).
Pho Yuen Dong is in President Plaza, which is just south of Quincy Center, heading toward East Braintree and Weymouth Landing. If you like Vietnamese food, check this place out while it's still not very well known!