Mainly the request/response logging. It's all in one place. I can click an xhr and it pops up right in the same window in a tabbed interface. I can see the request, response, headers, pretty json output if any. In chrome I click on an xhr, it takes me to a different tab where I have to scroll and find that request manually. I then have to switch back and forth manually if I need to go to other xhrs. Maybe this has changed in the last year? I don't know but that alone merited the switch.