Anecdotally, Chrome uses dramatically more memory and CPU than Safari for me (note: I typically have 100+ tabs open at once), and gives me somewhere between half and two thirds the battery life, for the same type of use. I have flash turned off for both and most ads blocked via /etc/hosts, so there shouldn’t be anything especially unfair in the results.

Google web apps (gmail, google maps, etc.) seem to be a particular offender.