First impression: Great choice for an architecture challenge.
Composition: Good use of the diagonal space. The diagonal line of the street leads the viewer through the image.
Exposure: You seem to of handled the reflective surface well. There don't appear to be any areas that are blown out (at least none that are large enough to be a distraction).
Impact: Impact is achieved by the strange shape of the building. I don't know if that's enough to keep a viewer without an interest in architecture interested in the image though.