Went to Pho So 1 in Randolph last week -- what a pleasant surprise. The place is in a hideous strip mall, next to a Shaw's market in downtown Randolph, with too bright lighting, but the Pho was as good as anything I've had in Chinatown, or at "real" Vietnamese places in SF and LA. There's about 12 different kinds of pho, including all the usual suspects (I like mine beef, no tripe, no tendon). Great flavor, plentiful noodles, big plate of add-ins, about $5.50. SO had the chicken, also very good.
They also have a fairly long menum of other dishes, we'll be back on some of the cold night coming up.