i also see this with some web sites which loads lots of javascript files. in firefox all tabs share same thread (this will be changed soon). therefore if some heavily scripted page loads, the whole firefox windows freezes until all scripts are executed.
i am running Palemoon x64 since a few years now, together with "NoScript" and some AdBlock fork addon. Works like a charme if configured correctly. My last "not responding" website is long ago. You are able to save your favorites in Palemoon. You are able to save your settings (or re-set them easily) in AdBlock forks, and NoScript has export functions, too. Complete setup with passwords and everything takes me less than 5 minutes. Just my opinion in this thread. Kind regards and please don't flame each other. This should be a nice tech forum, no horde of flaming "i-dont-give-a-fu**"-guys. Please calm down, think about what you said and if that is really necessary over the internet. You can have two opinions without battling each other. Have a nice evening.