Almost every other comment that have been posted so far are complaining that FF tabs are not independent processes. Let me express my contrarian opinion. For my use case FF is just excellent and has served me well, I have absolutely no complains now. There was a time when FF leaked, and held a lot of memory, that time has since passed, at least seams so. I regularly keep several hundreds of tabs open for months on en…
As a Firefox stalwart, my only sustained complaint about it is that the plug-in architecture is pretty crappy, but that's mostly a minor complaint so long as you avoid installing anything but very well understood and mature plug-ins. Chrome doesn't do all that much better here, since although its plugin architecture doesn't suffer quite so badly reliability-wise, plugins can still violate your privacy pretty much arbitrarily (modulo the relevant appstore blacklisting it, which is a pretty impotent reactive measure, as we've seen).
Firefox memory usage has always been, and I suppose will likely to continue to be far ahead of Chrome, since the desktop implementation is now largely identical to that used in Firefox OS.