Firefox was and is chided for feeling sluggish, crashing, and the likes. Most assume(d) these problems are related to the memory and process model. As well, the "memory bashing" was largely related to presuming the memory was "leaked," which turned out to be true. Such assumption have not been applied to Chrome, as far as I know. It was never anything I was much concerned with -- Firefox consuming too much memory. It was better than IE, in speed (re: not appearing to be sluggish) and tooling. Now Chrome takes a lead in those regards; mechanical test-results do not parallel my experiences.
You're talking about memory leaks as though they were a subjective thing (because nobody accused Chrome of having leaks, it doesn't). They are not. Objectively, both Gecko and WebKit have leaks, as a search through the bug trackers of both projects will confirm. (IMO, Gecko's approach to dealing with leaks -- a cycle collector -- is a superior approach to WebKit's more ad-hoc approach.)
As a developer, I couldn't possibly say with a straight face that a codebase like FF's or Chrome's, in size and language, are immune to leaks. I'm speaking about them the way every armchair developer has attacked FF over the years. I'm not saying they are right or wrong. I haven't invested myself in the issue, and I've stated or alluded to, several times, that it was not the "why" but the "what" that drove me. Firefox was slower and did less, so I switched. Anecdotal; 100% agree; I couldn't tell you exactly what I want; I don't necessarily have the time. For some, I'm sure the scale has dropped the opposite way (eg. they need more from FF's extension model).
Curiously, I went back to Iceweasel from Chromium after the latter kept crashing reproducible on some sites – among them plus.google.com and many others with Flash. So far, I have no encountered Iceweasel to crash, and the dev tools are only slightly worse than Chromium’s.
