I thought I'd posted this a couple of days ago but it was from my phone and it looks like something went astray..... I caught a very interesting video from @THEJATMN on youtube: He was looking at odd issues he'd seen when printing high poly count models. On deeper investigation he found that the same model with the same settings was giving different g-code from S3D! I initially thought it would be insignificant, due to the way S3D optimises the print but at times he found the extruder position could be 0.5mm different. This may not be an issue if the difference is along the extruder path, it may go a little further on a shallow arc before going onto the next point but if it's perpendicular to the path (away from the print centre) then it could be a big deal. I'm going to try to take a look at some code at some point, see if I can replicate the results.