The ups and downs of meals on wheels

Best
Chinatown: Bahn mi (Vietnamese sandwich), Saigon food cart; Chinese pancake, Chor-Ling, 44 Beach St.
Dorchester: Barbecued chicken and sides, M&M Ribs, 200 Geneva Ave.
Downtown Crossing: Chicken kebab pocket, Karo's Barbecue; steak burrito, Boston's Best Burritos; all-beef hot dog, Boston Red Dogs, Summer Street concourse.
Longwood Medical Area: Falafel hummus wrap, Sami's, Longwood Avenue at Avenue Louis Pasteur.
Harvard Square: Orange-carrot juice, mango-papaya-watermelon smoothie, smoothie cart, MBTA station main entrance.
MIT: Fresh spring rolls, Indochine, Main Street near Portland Street; pork chorizo tacos, Jose's Mexican; mango tofu salad, Goosebeary's, East Parking Lot, Main Street at Ames Street.

Worst
Boston Common: Fried dough with Boston cream, Daddy's Fried Dough; watermelon slush, Slush King, Tremont Street, outside Park Street station; lemonade, Boston Red Dogs, across from 175 Tremont St.
Downtown Crossing: Chicken pesto wrap, unnamed cart, Washington Street at Franklin Street.
Longwood Medical Area: Orange chicken, Chinese Kitchen, Longwood Avenue at Avenue Louis Pasteur.
MIT: Ginger scallion chicken, Chang Foods, Technology Square@MIT, Main Street near Portland Street; lamb shawarma, Jerusalem Cafe, East Parking Lot, Main at Ames .
JOE YONAN