We went from gas to electric so certainly energy saving but not money saving given the price difference between the fuels.
The other thing we discovered was that not all induction compatible pans are equal and some cheapo ones we had previously bought were very slow in responding whereas some almost as cheap cast iron skillets are much faster responding to induction than they were to gas. Our new SS pans seem a fair bit faster than the old cheap pans on gas but didn't do a proper A/B test.
The built in extraction is what made the install so difficult but is what we wanted so that when the full kitchen is done it can be on a peninsular without having to have an in ceiling hood or one that drops from the ceiling. We have no option for externally vented and as a recirculating extractor it seems to work fairly well.
Other than the install difficulty and unexpected cost of new pans overall very happy with the change and like many of the functions... 4 burners of equal power making it easy to move pans around and keep the same temp, a function to "auto-heat" so if you want level "6" power it'll actually start at max power and automatically drop down in steps to 6 as the pan gets to temp, surface is easy to clean, very fast response time, extractor better than expected and is automated by the hob etc.
Hated the last ceramic hob we had to the extent that when choosing between two flats where one had a gas hob it was a deciding factor.