I've been here a few times now, usually when I am looking for a meal on the run or something quick to eat.
There are a couple of other Vietnamese and pan-Asian places nearby but the clear advantage of Ben Thanh is that it is much less expensive. That said, the food is pretty simple but above average. The place is clean and the couple who run it are very lovely and welcoming. You can also bring your own wine. If you're looking for a fine dining experience, this may not be your spot, but for decent food at a great price, this hits the spot.