People often mistake high memory usage for memory leaks.
Chrome's performance is dependent on how you use it, and how much available RAM you have. It utilizes a single-process per tab, compared to the single-thread per tab approach other browsers use. A process is allocated its own virtual address space. So, for example, on a 32-bit version of Windows addressing can be up to 4GB, and 8TB on a 64-bit version. There's ups and downs to both approaches.
The average user, who doesn't open more than a few tabs, doesn't use many extensions, and browses page to page most likely isn't going to have anything short of good performance.
Now, one culprit of "memory leaks" is JavaScript (though, you can't have memory leaks in JavaScript, in the strictest sense). If you visit JavaScript heavy sites, you may see Chrome's memory footprint grow over time due to objects being kept alive, unintentionally (DOM leaks). As a process size gets bigger, the garbage collector may struggle to function (and not always clean up properly). If you have any specifics though, I'd love to hear them.
On topic though, the new FF version feels much more snappy than I remember!
Full disclaimer: I'm a Googler (though not part of the Chromium team).