I also keep a lot of tabs open, that's why I'm using Firefox and not Chrome. Firefox is very memory-efficient recently, whereas Chrome is a memory hog and can't handle the number of tabs I keep open in Firefox.

Firefox also does a neat thing with tabs that have been opened and not used in a long time, effectively unloading the website and reloading it once you visit the tab (for some reason it doesn't do so with tabs that I keep open in the background on purpose, like Gmail). They also had memory fragmentation problems, which they gradually fixed and now I'm very, very pleased with Firefox. Chrome is really draining my resources at 30 tabs opened, whereas I've had Firefox open with 100 tabs without issues.

The one process per tab model does have an advantage for misbehaving long-running apps. For example I had problems with Asana at some point, as I think it was leaking memory or something and Firefox couldn't handle it. In Chrome, you can find out what misbehaving tabs you have and simply close it.

If Firefox can switch to the one process per tab model, but somehow keep its current efficiency in managing memory, that would be so awesome.