Madame Nhu is reasonably in price, has good portion sizes, a variety of stuff on the menu, is in a good location, provides tasty food and prompt service. It ticks all the boxes.
Go for the Beef Pho.

During the week you can enjoy a express style pho here at the galleries. THey have really fast and efficient service.
I recommend eating here for a quick healthy good quality meal during the lunch hour if you feel like vietnamese

Large portion sizes and reasonable price when sharing. Delicious vietnamese food -- I'll be going back to try the pho!

Approximate cost: $23

I love the pulled pork rice paper rolls at Madame Nhu, they are so delicious and fresh. The fried chicken with rice is also very tasty. I love that you can order your food here and then eat your meals in the small seating area next to their restaurant. The service is also very good too.

This canteen is located near Town Hall below where I work so I eat here every week. I seriously can't fault the food, especially the soups. Haven't had anything on the menu that I didn't like. I also find that their level of hygeine is next to none. Their kitchen is completely open. No hidden back kitchen either. You can actually stand there and watch the chefs prepare your food. They all wear gloves and the kitchen is very clean and modern. So I don't really understand one of the comments below. Finding a caterpillar on a herb isn't the same as finding a cockroach. If anything, it's a sign that the vegies are fresh from the farm. And it hasn't been treated with chemicals and deadly pesticides. I can only speak from my experience but the herbs I get with my soup are always fresh and wet (a sign that it's washed). Anyway, to sum up, the food is fantastic, the service is what you'd expect from a food court, and the price is very reasonable for the city!

Approximate cost: $10

Yummy food, bad hygiene and worst service.
Their Pho is not bad for Sydney CBD (but can't beat local viet places in suburbs in terms of size and value), I used to be a regular but won't be going back ANYMORE!
I used to go cos you could get decent portion and quality around $10 (it's cheap compared to $12 salads next door) However, my last experience with Madame Nhu was bad enough to make me stop going there...
When i was slurping my pho noodles, my right hand felt very itchy. Knowing the dimmed lights in the food hall I didn't know what it was until I took a good look. It was worms from the raw viet herbs (which, by the way, looked VERY dark and off so I only picked the fresh bits in) crawling onto my hand!!! I killed them out of horror and was in shock so I totally forgot to go back to the restaurant and tell them what just happened. I returned the next day telling them what happened to me the day before and they just looked at me blankly with no apology or feel embarrassed about what happened. I was not happy about their reaction so I'm here to write about my experience so people could choose wisely about their restaurant. Hopefully the restaurant sees this review one day and do make some improvement about the hygiene and service.

Approximate cost: $10