Well it is not finished yet but I as Nick said I have noticed that if you put your ear to the wall you can easily hear what's being said outside.
But we have faced a number of issues. I really dislike having 9mm osb as the thing everything needs to grip on to. We have 85kg per sqm of brick sips hanging on the outside walls and I do worry if 9mm Osb can take it. Also we are currently working on the inside doing an airtight membrane and the battons over the top which is fine, but the moment you try to screw anything substantial to the wall like CLS the screws just won't grip due to how thin the walls are. Ive also noticed our huge sips roof panels dont seem to perfectly line up.
Lastly the main benefit of Sips seems to be the build time but once your factor in the year that it takes to really nail down the sips design, get it manufactured and then to site, it really isn't much faster. I would also never touch ICF after seeing someone down my road build one. Timber frame seems to be the most tried and tested sustainable way forwards in my opinion.