It's quite memory hungry. Not saying leaking per-se, but my 16GB machine at work started swapping heavily mostly due to Firefox today.
Only had about 15 active tabs (though a number of dormant ones since last FF restart). Between the various processes, FF was using about 6-7GB of memory. Closing almost all of the tabs reclaimed about 2GB, so still a lot left over.
That said I'm not too bothered, I can restart FF every other week or so.
My main concern is the questionable use of Studies and other experimental paths to test things like advertising in Firefox. I don't like this. I would prefer my browser to be more neutral.
Of course I can disable it if I want. But, I wish I could simply trust my browser vendor to do the right thing.
The browser itself seems solid, I've been happy since Quantum and look forward to seeing WebRender rollout.
A lot of usability issues, for example: You can't disable Ctrl-Q on Linux due to a bug that they do not seem to be willing to fix. In the past I used to depend on the "are you sure you want to close N tabs?" confirmation dialog thing but now they have removed it.
