We went to Vietnam in Dec 2016–Jan 2017 and enjoyed every minute of it. Here are food places we recommend in Saigon and Hanoi:

Saigon

• Phở Thanh Bình, Nguyễn Thị Minh Khai. Our favorite pho of the trip. A bit sweeter/more complex than the northern/Hanoi style.
• Banh Mi, 37 Nguyen Trai - we liked this banh mi, had some great bread.
• Co Lan, 44 Nguyễn Trãi Chicken curry noodles! (Ca ri ga) - we really enjoyed this meal, it’s a bit far from the main area.
• Com Tam, 74 Nguyen Van Cu, opens early 7 AM closes 3 PM, Vietnamese pork chop with broken rice, very popular dish for breakfast in southern Vietnam
• Com Ga Su Su, 55 Tú Xương, D3 - We wanted to go here, but was closed at night by the time we got there. Our friend says “amazing, waterfall (oil drips onto the chicken during cooking like a waterfall) fried chicken with chicken rice”
• Hủ Tiếu Nam Vang Nhân Quán, 488 Nguyễn Thị Minh Khai - we enjoyed the hu tieu style noodles here; I got the dry, she got the soup version, both were excellent.
• Maison Marou, 167 Calmette, Nguyễn Thái Bình: Fantastic chocolatier with great decor and the most beautiful packaging. Try pastries, and more importantly, buy a LOT of chocolate to bring home for yourself and gifts. It’s some of the best i’ve ever had.

Hanoi

• Cha Ca Thang Long, 31 Đường Thành - local joint doing cha ca, a tumeric fish dish that’s famous in Hanoi.
• Pho Gia Truyen, 49 Bat Dan - Some of the most tender beef I’ve had in pho and the best we had in Hanoi. Don’t forget to order quay with your pho, fried bread that adds texture and fried goodness to the meal :)
• Chicken soup street, Hàng Hòm - this entire street is famous for the chicken pho stalls; we chose one that looked popular and loved it!
• AVOID: Dac Kim Bun Cha - listed as one of the famous ones in the area; looks like it got waaaaay too popular, their food was not fresh and it was loaded with tourists. Didn't see any locals. Avoid! Instead, we went to…
• Bún chả, 34 Hàng Than: we enjoyed this place’s bun cha and loved the kitchen in the tiny alley. Don’t forget to get spring rolls, they are delicate and crispy!
• Coconut jelly, 54 Hàng Cót: serves the best and most refreshing coconut jelly i’ve ever had, served in a coconut shell.
• Nonna street food map: found this map to be very useful to understand the food of the area. Didn’t go wrong with the choices we made from this (chicken soup street, coconut jelly) and other random places we tried. Wish we had more time to explore!

General tips

1. Get a SIM card when you arrive in the airport. Get it for the data / google maps while walking around. I paid $10. bring cash, they don’t take credit.
2. Careful of anybody who offers you a taxi @ Ho Chi Minh airport. Stick with Vina Sun or Mai Linh - they have meters and generally professional drivers.
3. Many of the taxi drivers don’t speak english, so try to have your destination written down for them to read
4. I really enjoyed using Google Trips as an app - it remembers everything you starred in Google Maps and helps you get context to things to see!
5. If you are getting a visa on arrival in Ho Chi Minh, make sure you bring the exact amount of cash (they take USD), and if you got the visa approval letter through a 3rd party, I'd inquire about and pay for the "fast track" service where an agent stands in line to get it for you. They have men who seem to have a special arrangement with the visa office. I didn't get this service and I ended up standing in line behind a mob of angry Russians for 2 hours as I had to listen carefully for my name called by a woman speaking in broken Russian and English. It wasn't fun.