This extension is superb on a PC!
Pros:
* Saves tabs for easy access later
* Can import/export tabs for use on another device
* This extension doesn't scrape and sell your data AFIK

Cons:
* Currently on Android Firefox some features such as adding current tab or just one page at a time don't seem to be available, but I know this scenario is probably kind of rare.
* Firefox on Android currently doesn't let OneTab save inactive tabs, so you have to open those tabs to make them active and then save to OneTab

I love the pros enough that I'm ok with the cons and can just work around them.