Notice the dark faces. Even though it's not in shadow from anywhere and all normals are correctly facing as far as i can tell. I have also tried different/fresh material but that doesn't seem to affect this issue.
edit: replies to the comments (dunno how else to answer them) :
1. the link is invalid. goes to a 404 page.
2. the lighting setup is a the default blender sun lamp.
3. the mesh is not distorted at all. its appearance is due to the weird rendering issue.
4. thanks for the correct link. this awesome service should be integrated directly into this forum imo.
i see that this question is a duplicate, so moderators feel free to delete if required. I did search for an answer here before posting, guess I was using wrong keywords.