I gotta agree with rob here on the infill. I have no problems getting super solid and strong infill in s3d. Almost everything i print needs to have strength in some way since they are functional and usually load bearing. S3ds infill is as strong as anyone elses. Its true it prints every other layer but it extrudes at double the dia so the walls are thick and solid. It seems alit of people complain about the infill situation. I just dont think that many people understand the settings. Of course s3d does have alot of setting so that not surprising really.