This add-on has nothing to do with mining for nonsense like Bitcoins and it's not okay to offend me. No, the lot of positive reviews are not bogus, most users are very happy with the add-on. There is still no (!) bug report on the issues tracker. There is not one person reported hangs.

But yes, if you have a lot of bookmarks of course it's a lot of work for Firefox to load all of them. That's not a issue of the add-on.

Your comment is wrong, offending and not constructive at all.