Chrome chews through a lot of resources on my machine. Firefox is a lot lighter. And I think it will still be lighter since they're targeting a 2-process model instead of Chrome's (let me count) 17 that it just launched on startup.

Chrome is utterly unsuited to the use case of leaving hundreds of tabs open, which happens often to me, as I only bother updating/cleaning my bookmarks a couple of times a year. There's three main issues with Chrome:

1) Nothing I've found that works nearly as well as Tree Style Tab.

2) Chrome always reloads all tabs when the browser starts up. Firefox, at least with Session Manager, will only load old tabs when I activate them.

3) Chrome takes up way more memory. That's partly due to #2, but partly inherent in the multi-process model.

The Chrome UI also gets weird under load. With Firefox, it's easy to tell when it's laggy. With Chrome, the UI seems asynchronous, but there's no consideration for actions taking a long time, so you can get the annoying feeling of clicking with nothing obvious happening.