The biggest difference that I've noticed btw. Chrome and Safari is about 1GB free memory when using Chrome. No exaggeration. Safari has gotten INSANELY bloated. I've been using a Chromium nightly for about two weeks and it's like night and day. Safari is beach-balls galore, while Chromium (and now Chrome) is just speedy and compact.
I quit a Safari session I was running this morning with TWO TABS and it freed 750MB. That is so wrong.