quan thanh is basically the tastier version of trang down the road, popular enough to have two entirely separate restaurants focusing on different cuisines right next to each other.
we usually tend to go more often for vietnamese dishes, their food is always very flavourful and in very good portions for the price. i think similar to trang it's always full because it's never not worth it, it's a way to have a good dinner or lunch out without breaking the bank.
our favourite dish is definitely their braised beef noodle soup, it's very hearty so be warned that it's not really a lot like pho; the broth is fatty and rich, the meat is always incredibly tender and so are the vegetables. be very careful, it will stain your clothes!
service is decent, they almost always have someone at the door to ask if you'd rather have dine in or takeaway, the staff is friendly enough, it's understandable that they're usually in a rush with the amount of people they have to serve. the decor isn't that fantastic either, you're definitely going for the food.
overall, if you just want to have a decent dinner in a very livelyrestaurantwithout paying too much, then this place is quite good.