I've only been once a while ago, the steak frites came cut and was I believe was skirt steak. I was hoping a nice bistro steak frites, it didn't meet my expectations. So, I would say pass on that.
Hmmm... last time I was there they definitely had a strip steak. Just checked their online menu and they do have a "Bistro" strip steak. Their "Steak Frites", on the other hand, clearly says skirt steak (and at $18 you're not gonna get much more than that).
In any case, I think Marche is still a great spot. We don't go nearly often enough, just because the city offers way too many options. We were there a few months ago with two other couples and our orders ran the gamut from steak to fish to fowl and nobody was dissatisfied with any of the courses.