This extension does not play alongside hardware FIDO U2F keys. Since it's important to register multiple keys, this makes life extremely difficult.

Been using krypton for over a year now and it works great. Can also save and copy your ssh keys for you to your machines with their application (or the traditional way.)

Cannot add sites that aren't supported. I don't want to have two apps for authentication, so I might as well use Authy instead.