Eiffel towers are fun and challenging. One person helped out by adding some support and filling out the railing. It's this model:
http://www.thingiverse.com/thing:337409
S3D can't seem to slice it successfully. Lots of portions are just missing.
However, Makerware manages to slice OK! Takes a much longer time to slice, but it works, and everything seems to be there.
In general, S3D seems to work much better for me. Is this a fixable bug?