Yesss, as good as it gets. I love these types of places that are no fuss (it's two guys in a large…read morestand at the edge of an open concrete area), affordable, great food, worth whatever wait in line (although I didn't really wait -- there were maybe two people in front of me).
This was on my list as the place I wanted to get frites before I left Brussels, and the fact that a friend who now lives here also mentioned it, sealed the deal even more.
Such fresh frites served in a cone (the small is enough for one hungry person) and with a huge dollop of sauce for your heart's content. The andalouse sauce really hit the spot -- it's a Belgian speciality -- like, a creamy tomato-paste sauce with a kick. Reminds me of thousand island but more tangy -- somewhere between a thousand island and chipotle sauce.
If you're looking for great frites, in a town filled with lots of good options, this is a place you definitely want to stop at! :)