Chrome uses more memory, but for good reason. I think they load more stuff in RAM so the browser works faster, and there's also the sandbox security feature, which makes it so tabs don't share memory, so that must add quite a bit, too. That being said, I wouldn't mind if the Chrome team worked on optimizing RAM usage as well, if they aren't doing it already.
What is the basis of your belief that their increased memory usage is because they "load more stuff in RAM so the browser works faster"? In my experience working on MemShrink, almost all of the things we have fixed are the browser using more memory for no particularly good reason, and I would be surprised if this wasn't also the case in Chrome. You are right that sandboxing does incur some overhead, but I'm not sure how much. But I agree with your overall point, that memory usage is by itself is not as important as overall system performance.
