I have posted the blow message in the general topics list.
viewtopic.php?f=8&t=9840
In short, S3D is in my opinion not behaving like it should.
When slicing the item mentioned in the post above, S3D will not finish a closed shell but instead print it in several parts with gaps in between.
Also, I have found that S3D sometimes simply skips an outline which is very thin, of tries to print it separately, which makes for a weak and not nice looking print.
Basically every time, the same model will print fine with Cura.