For the first 50, your lines are overall very clean, with only minimal traces of arcing here and there, like in box 10. Your convergences also show good accuracy overall, though I noticed some lines pair off and converge towards two vanishing points, like box 11, box 31, and box 50.

For the next 50, as before, your lines are very clean. Very little arcing is present outside of box 81, which is not particularly dramatic. Your convergences show improvement, as well, though there are still some instances of lines pairing off, like box 58, box 70, and box 96.

For the last 150, your lines remain impressively clean throughout the rest of the challenge, showing very good control and technique. Your convergences also show continued improvement; box 224came out very well, for example. The only lingering point that I see is that some lines continue to pair off, like box 115, box 173, and box 229. In these boxes, the inner lines (green and orange in this diagram) diverge instead of converging at the vanishing point. Keeping in mind the angles of neighboring lines can help when planning the box's construction.

As an aside, box 110 is missing some line extensions. It's not a major issue since it didn't happen often, but I want to point it out for future reference.

All said, you did very well. I'm going to mark this challenge as complete.