Owner of 2017 MacBook Pro 15
didn't update my OS from Sierra to High Sierra till yesterday but boy oh boy I am glad I now did!
the battery life is so much better right now its amazing
as you can see I been on the battery for 7 hours , watching Netflix , browsing multiple tabs on chrome and safari - and mostly watching a live video feed on chrome that before would have drain the battery super fast and I am only on 58% - before updating I would guess it would be around the 20-25% about now - or maybe even lower. (brightness about 50%)
So if you are still on Sierra - my advice is don't hesitate - update!
didn't update my OS from Sierra to High Sierra till yesterday but boy oh boy I am glad I now did!
the battery life is so much better right now its amazing

as you can see I been on the battery for 7 hours , watching Netflix , browsing multiple tabs on chrome and safari - and mostly watching a live video feed on chrome that before would have drain the battery super fast and I am only on 58% - before updating I would guess it would be around the 20-25% about now - or maybe even lower. (brightness about 50%)
So if you are still on Sierra - my advice is don't hesitate - update!